21265816147455 has 256 divisors, whose sum is σ = 41855333990400. Its totient is φ = 9085964451840.

The previous prime is 21265816147447. The next prime is 21265816147481. The reversal of 21265816147455 is 55474161856212.

It is not a de Polignac number, because 21265816147455 - 2³ = 21265816147447 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (57).

It is a junction number, because it is equal to n+sod(n) for n = 21265816147395 and 21265816147404.

It is a congruent number.

It is an unprimeable number.

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 255 ways as a sum of consecutive naturals, for example, 4337304534 + ... + 4337309436.

It is an arithmetic number, because the mean of its divisors is an integer number (163497398400).

Almost surely, 2^{21265816147455} is an apocalyptic number.

21265816147455 is a deficient number, since it is larger than the sum of its proper divisors (20589517842945).

21265816147455 is a wasteful number, since it uses less digits than its factorization.

21265816147455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5894.

The product of its digits is 16128000, while the sum is 57.

The spelling of 21265816147455 in words is "twenty-one trillion, two hundred sixty-five billion, eight hundred sixteen million, one hundred forty-seven thousand, four hundred fifty-five".