20445338661 has 24 divisors (see below), whose sum is σ = 30007085472. Its totient is φ = 12373284000.

The previous prime is 20445338647. The next prime is 20445338689. The reversal of 20445338661 is 16683354402.

It is not a de Polignac number, because 20445338661 - 2⁵ = 20445338629 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20445338611) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 214290 + ... + 294636.

It is an arithmetic number, because the mean of its divisors is an integer number (1250295228).

Almost surely, 2^20445338661 is an apocalyptic number.

It is an amenable number.

20445338661 is a deficient number, since it is larger than the sum of its proper divisors (9561746811).

20445338661 is a wasteful number, since it uses less digits than its factorization.

20445338661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 81073 (or 81062 counting only the distinct ones).

The product of its (nonzero) digits is 414720, while the sum is 42.

The spelling of 20445338661 in words is "twenty billion, four hundred forty-five million, three hundred thirty-eight thousand, six hundred sixty-one".