21431055265 has 16 divisors (see below), whose sum is σ = 26349797376. Its totient is φ = 16723324800.

The previous prime is 21431055259. The next prime is 21431055281. The reversal of 21431055265 is 56255013412.

It is not a de Polignac number, because 21431055265 - 2³ = 21431055257 is a prime.

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 21431055265.

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, 1672774 + ... + 1685536.

It is an arithmetic number, because the mean of its divisors is an integer number (1646862336).

Almost surely, 2^21431055265 is an apocalyptic number.

It is an amenable number.

21431055265 is a deficient number, since it is larger than the sum of its proper divisors (4918742111).

21431055265 is a wasteful number, since it uses less digits than its factorization.

21431055265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21000.

The product of its (nonzero) digits is 36000, while the sum is 34.

Adding to 21431055265 its reverse (56255013412), we get a palindrome (77686068677).

The spelling of 21431055265 in words is "twenty-one billion, four hundred thirty-one million, fifty-five thousand, two hundred sixty-five".