21001111131231 has 108 divisors (see below), whose sum is σ = 38845920909432. Its totient is φ = 10893145032000.

The previous prime is 21001111131173. The next prime is 21001111131239. The reversal of 21001111131231 is 13213111110012.

21001111131231 is a `hidden beast` number, since 210 + 0 + 1 + 1 + 111 + 312 + 31 = 666.

It is not a de Polignac number, because 21001111131231 - 2²¹ = 21001109034079 is a prime.

It is a super-2 number, since 2×21001111131231² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21001111131239) by changing a digit.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 34973916 + ... + 35569326.

Almost surely, 2^{21001111131231} is an apocalyptic number.

21001111131231 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

21001111131231 is a deficient number, since it is larger than the sum of its proper divisors (17844809778201).

21001111131231 is a wasteful number, since it uses less digits than its factorization.

21001111131231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 596114 (or 596093 counting only the distinct ones).

The product of its (nonzero) digits is 36, while the sum is 18.

Adding to 21001111131231 its reverse (13213111110012), we get a palindrome (34214222241243).

The spelling of 21001111131231 in words is "twenty-one trillion, one billion, one hundred eleven million, one hundred thirty-one thousand, two hundred thirty-one".