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BaseRepresentation
bin11100111110011110…
…110000011100100101
32222022022122020110022
4130332132300130211
51002204413134341
622143152004525
72151003213452
oct347636603445
988268566408
1031113021221
1112216542387
126043830745
132c1ab54839
1417121b6829
15c216d2e4b
hex73e7b0725

31113021221 has 2 divisors, whose sum is σ = 31113021222. Its totient is φ = 31113021220.

The previous prime is 31113021197. The next prime is 31113021293. The reversal of 31113021221 is 12212031113.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 30385370596 + 727650625 = 174314^2 + 26975^2 .

It is an emirp because it is prime and its reverse (12212031113) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2k-31113021221 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 31113021221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31113024221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15556510610 + 15556510611.

It is an arithmetic number, because the mean of its divisors is an integer number (15556510611).

Almost surely, 231113021221 is an apocalyptic number.

It is an amenable number.

31113021221 is a deficient number, since it is larger than the sum of its proper divisors (1).

31113021221 is an equidigital number, since it uses as much as digits as its factorization.

31113021221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 17.

Adding to 31113021221 its reverse (12212031113), we get a palindrome (43325052334).

The spelling of 31113021221 in words is "thirty-one billion, one hundred thirteen million, twenty-one thousand, two hundred twenty-one".