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21101100820 = 2258111300931
BaseRepresentation
bin10011101001101110…
…010011111100010100
32000110120102222121121
4103221232103330110
5321203340211240
613405501453324
71344622253242
oct235156237424
960416388547
1021101100820
118a490263a8
12410a871244
131cb3852697
14104262d792
1583776d04a
hex4e9b93f14

21101100820 has 24 divisors (see below), whose sum is σ = 44366984928. Its totient is φ = 8430026400.

The previous prime is 21101100817. The next prime is 21101100821. The reversal of 21101100820 is 2800110112.

It is a junction number, because it is equal to n+sod(n) for n = 21101100794 and 21101100803.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21101100821) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 634246 + ... + 666685.

It is an arithmetic number, because the mean of its divisors is an integer number (1848624372).

Almost surely, 221101100820 is an apocalyptic number.

21101100820 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21101100820 is an abundant number, since it is smaller than the sum of its proper divisors (23265884108).

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

21101100820 is a wasteful number, since it uses less digits than its factorization.

21101100820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1301751 (or 1301749 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21101100820 its reverse (2800110112), we get a palindrome (23901210932).

The spelling of 21101100820 in words is "twenty-one billion, one hundred one million, one hundred thousand, eight hundred twenty".

Divisors: 1 2 4 5 10 20 811 1622 3244 4055 8110 16220 1300931 2601862 5203724 6504655 13009310 26018620 1055055041 2110110082 4220220164 5275275205 10550550410 21101100820