21765325051665 has 48 divisors (see below), whose sum is σ = 41317227282240. Its totient is φ = 10533622746240.

The previous prime is 21765325051579. The next prime is 21765325051669. The reversal of 21765325051665 is 56615052356712.

21765325051665 is a `hidden beast` number, since 2 + 1 + 7 + 6 + 532 + 50 + 51 + 6 + 6 + 5 = 666.

It is not a de Polignac number, because 21765325051665 - 2⁹ = 21765325051153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21765325051669) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 315267891 + ... + 315336920.

It is an arithmetic number, because the mean of its divisors is an integer number (860775568380).

Almost surely, 2^{21765325051665} is an apocalyptic number.

It is an amenable number.

21765325051665 is a deficient number, since it is larger than the sum of its proper divisors (19551902230575).

21765325051665 is a wasteful number, since it uses less digits than its factorization.

21765325051665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 630604894 (or 630604891 counting only the distinct ones).

The product of its (nonzero) digits is 11340000, while the sum is 54.

The spelling of 21765325051665 in words is "twenty-one trillion, seven hundred sixty-five billion, three hundred twenty-five million, fifty-one thousand, six hundred sixty-five".