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31100312220 = 22353471493771
BaseRepresentation
bin11100111101101110…
…010001101010011100
32222021102201112222120
4130331232101222130
51002143134442340
622142015342540
72150460202125
oct347556215234
988242645876
1031100312220
111220a35197a
12603b521a50
132c18324c13
14171062904c
15c205224d0
hex73db91a9c

31100312220 has 48 divisors (see below), whose sum is σ = 87331886208. Its totient is φ = 8269510720.

The previous prime is 31100312213. The next prime is 31100312233. The reversal of 31100312220 is 2221300113.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 31100312220.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 726066 + ... + 767705.

It is an arithmetic number, because the mean of its divisors is an integer number (1819414296).

Almost surely, 231100312220 is an apocalyptic number.

31100312220 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

31100312220 is an abundant number, since it is smaller than the sum of its proper divisors (56231573988).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31100312220 is a wasteful number, since it uses less digits than its factorization.

31100312220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1494130 (or 1494128 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 15.

Adding to 31100312220 its reverse (2221300113), we get a palindrome (33321612333).

The spelling of 31100312220 in words is "thirty-one billion, one hundred million, three hundred twelve thousand, two hundred twenty".

Divisors: 1 2 3 4 5 6 10 12 15 20 30 60 347 694 1041 1388 1735 2082 3470 4164 5205 6940 10410 20820 1493771 2987542 4481313 5975084 7468855 8962626 14937710 17925252 22406565 29875420 44813130 89626260 518338537 1036677074 1555015611 2073354148 2591692685 3110031222 5183385370 6220062444 7775078055 10366770740 15550156110 31100312220