20637724161665 has 16 divisors (see below), whose sum is σ = 27829867500288. Its totient is φ = 14577549640896.

The previous prime is 20637724161653. The next prime is 20637724161667. The reversal of 20637724161665 is 56616142773602.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 20637724161665 - 2¹⁸ = 20637723899521 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 20637724161665.

It is not an unprimeable number, because it can be changed into a prime (20637724161667) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 6902247389 + ... + 6902250378.

It is an arithmetic number, because the mean of its divisors is an integer number (1739366718768).

Almost surely, 2^{20637724161665} is an apocalyptic number.

It is an amenable number.

20637724161665 is a deficient number, since it is larger than the sum of its proper divisors (7192143338623).

20637724161665 is a wasteful number, since it uses less digits than its factorization.

20637724161665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13804497808.

The product of its (nonzero) digits is 15240960, while the sum is 56.

The spelling of 20637724161665 in words is "twenty trillion, six hundred thirty-seven billion, seven hundred twenty-four million, one hundred sixty-one thousand, six hundred sixty-five".