21648402542865 has 128 divisors (see below), whose sum is σ = 40876903710720. Its totient is φ = 9579584102400.

The previous prime is 21648402542831. The next prime is 21648402542867. The reversal of 21648402542865 is 56824520484612.

It is not a de Polignac number, because 21648402542865 - 2⁹ = 21648402542353 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21648402542867) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 155270785 + ... + 155410145.

It is an arithmetic number, because the mean of its divisors is an integer number (319350810240).

Almost surely, 2^{21648402542865} is an apocalyptic number.

It is an amenable number.

21648402542865 is a deficient number, since it is larger than the sum of its proper divisors (19228501167855).

21648402542865 is a wasteful number, since it uses less digits than its factorization.

21648402542865 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139823.

The product of its (nonzero) digits is 29491200, while the sum is 57.

The spelling of 21648402542865 in words is "twenty-one trillion, six hundred forty-eight billion, four hundred two million, five hundred forty-two thousand, eight hundred sixty-five".