21557053265 has 24 divisors (see below), whose sum is σ = 29351180544. Its totient is φ = 15172106400.

The previous prime is 21557053253. The next prime is 21557053277. The reversal of 21557053265 is 56235075512.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21557053253) and next prime (21557053277).

It is not a de Polignac number, because 21557053265 - 2⁸ = 21557053009 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 555947 + ... + 593456.

It is an arithmetic number, because the mean of its divisors is an integer number (1222965856).

Almost surely, 2^21557053265 is an apocalyptic number.

It is an amenable number.

21557053265 is a deficient number, since it is larger than the sum of its proper divisors (7794127279).

21557053265 is a wasteful number, since it uses less digits than its factorization.

21557053265 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1149461 (or 1149450 counting only the distinct ones).

The product of its (nonzero) digits is 315000, while the sum is 41.

The spelling of 21557053265 in words is "twenty-one billion, five hundred fifty-seven million, fifty-three thousand, two hundred sixty-five".