21265016875 has 10 divisors (see below), whose sum is σ = 26572765868. Its totient is φ = 17012013000.

The previous prime is 21265016833. The next prime is 21265016879. The reversal of 21265016875 is 57861056212.

It is not a de Polignac number, because 21265016875 - 2⁹ = 21265016363 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21265016879) by changing a digit.

It is a polite number, since it can be written in 9 ways as a sum of consecutive naturals, for example, 17011389 + ... + 17012638.

Almost surely, 2^21265016875 is an apocalyptic number.

21265016875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21265016875 is a deficient number, since it is larger than the sum of its proper divisors (5307748993).

21265016875 is an frugal number, since it uses more digits than its factorization.

21265016875 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 34024047 (or 34024032 counting only the distinct ones).

The product of its (nonzero) digits is 201600, while the sum is 43.

The spelling of 21265016875 in words is "twenty-one billion, two hundred sixty-five million, sixteen thousand, eight hundred seventy-five".