20431664 has 20 divisors (see below), whose sum is σ = 43185480. Its totient is φ = 9287040.

The previous prime is 20431661. The next prime is 20431667. The reversal of 20431664 is 46613402.

It is an interprime number because it is at equal distance from previous prime (20431661) and next prime (20431667).

It is not an unprimeable number, because it can be changed into a prime (20431661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57869 + ... + 58220.

It is an arithmetic number, because the mean of its divisors is an integer number (2159274).

Almost surely, 2^20431664 is an apocalyptic number.

It is an amenable number.

20431664 is an abundant number, since it is smaller than the sum of its proper divisors (22753816).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20431664 is a wasteful number, since it uses less digits than its factorization.

20431664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 116108 (or 116102 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 26.

The square root of 20431664 is about 4520.1398208463. The cubic root of 20431664 is about 273.3807386877.

The spelling of 20431664 in words is "twenty million, four hundred thirty-one thousand, six hundred sixty-four".