21251011115431 has 16 divisors (see below), whose sum is σ = 22012784640000. Its totient is φ = 20491181692128.

The previous prime is 21251011115401. The next prime is 21251011115497. The reversal of 21251011115431 is 13451111015212.

It is a cyclic number.

It is not a de Polignac number, because 21251011115431 - 2¹⁹ = 21251010591143 is a prime.

It is a super-2 number, since 2×21251011115431² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21251011115431.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21251011115401) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (29) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 100372320 + ... + 100583818.

It is an arithmetic number, because the mean of its divisors is an integer number (1375799040000).

Almost surely, 2^{21251011115431} is an apocalyptic number.

21251011115431 is a deficient number, since it is larger than the sum of its proper divisors (761773524569).

21251011115431 is a wasteful number, since it uses less digits than its factorization.

21251011115431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 216078.

The product of its (nonzero) digits is 1200, while the sum is 28.

The spelling of 21251011115431 in words is "twenty-one trillion, two hundred fifty-one billion, eleven million, one hundred fifteen thousand, four hundred thirty-one".