21265343605 has 64 divisors (see below), whose sum is σ = 29927024640. Its totient is φ = 14334566400.

The previous prime is 21265343579. The next prime is 21265343633. The reversal of 21265343605 is 50634356212.

It is not a de Polignac number, because 21265343605 - 2³³ = 12675409013 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 35033212 + ... + 35033818.

It is an arithmetic number, because the mean of its divisors is an integer number (467609760).

Almost surely, 2^21265343605 is an apocalyptic number.

It is an amenable number.

21265343605 is a deficient number, since it is larger than the sum of its proper divisors (8661681035).

21265343605 is a wasteful number, since it uses less digits than its factorization.

21265343605 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1150.

The product of its (nonzero) digits is 129600, while the sum is 37.

Adding to 21265343605 its reverse (50634356212), we get a palindrome (71899699817).

The spelling of 21265343605 in words is "twenty-one billion, two hundred sixty-five million, three hundred forty-three thousand, six hundred five".