21165737564 has 12 divisors (see below), whose sum is σ = 37456221600. Its totient is φ = 10463959968.

The previous prime is 21165737543. The next prime is 21165737573. The reversal of 21165737564 is 46573756112.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 29726804 + ... + 29727515.

It is an arithmetic number, because the mean of its divisors is an integer number (3121351800).

Almost surely, 2^21165737564 is an apocalyptic number.

It is an amenable number.

21165737564 is a deficient number, since it is larger than the sum of its proper divisors (16290484036).

21165737564 is a wasteful number, since it uses less digits than its factorization.

21165737564 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 59454412 (or 59454410 counting only the distinct ones).

The product of its digits is 1058400, while the sum is 47.

The spelling of 21165737564 in words is "twenty-one billion, one hundred sixty-five million, seven hundred thirty-seven thousand, five hundred sixty-four".