21645201465 has 96 divisors (see below), whose sum is σ = 40896868896. Its totient is φ = 10546053120.

The previous prime is 21645201433. The next prime is 21645201467. The reversal of 21645201465 is 56410254612.

21645201465 is a `hidden beast` number, since 2 + 1 + 64 + 520 + 14 + 65 = 666.

It can be written as a sum of positive squares in 16 ways, for example, as 499388409 + 21145813056 = 22347^2 + 145416^2 .

It is not a de Polignac number, because 21645201465 - 2⁵ = 21645201433 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21645201467) by changing a digit.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 18142909 + ... + 18144101.

It is an arithmetic number, because the mean of its divisors is an integer number (426009051).

Almost surely, 2^21645201465 is an apocalyptic number.

It is an amenable number.

21645201465 is a deficient number, since it is larger than the sum of its proper divisors (19251667431).

21645201465 is a wasteful number, since it uses less digits than its factorization.

21645201465 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1899 (or 1896 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 36.

The spelling of 21645201465 in words is "twenty-one billion, six hundred forty-five million, two hundred one thousand, four hundred sixty-five".