21424762665 has 36 divisors (see below), whose sum is σ = 37850383116. Its totient is φ = 11210878848.

The previous prime is 21424762649. The next prime is 21424762727. The reversal of 21424762665 is 56626742412.

21424762665 is a `hidden beast` number, since 2 + 14 + 2 + 4 + 7 + 626 + 6 + 5 = 666.

It can be written as a sum of positive squares in 6 ways, for example, as 3239431056 + 18185331609 = 56916^2 + 134853^2 .

It is not a de Polignac number, because 21424762665 - 2⁴ = 21424762649 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a self number, because there is not a number n which added to its sum of digits gives 21424762665.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 41659 + ... + 211151.

It is an arithmetic number, because the mean of its divisors is an integer number (1051399531).

Almost surely, 2^21424762665 is an apocalyptic number.

It is an amenable number.

21424762665 is a deficient number, since it is larger than the sum of its proper divisors (16425620451).

21424762665 is a wasteful number, since it uses less digits than its factorization.

21424762665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 169610 (or 169554 counting only the distinct ones).

The product of its digits is 967680, while the sum is 45.

The spelling of 21424762665 in words is "twenty-one billion, four hundred twenty-four million, seven hundred sixty-two thousand, six hundred sixty-five".