20642431 has 4 divisors (see below), whose sum is σ = 21539952. Its totient is φ = 19744912.

The previous prime is 20642423. The next prime is 20642443. The reversal of 20642431 is 13424602.

It is a happy number.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 20642431 - 2³ = 20642423 is a prime.

It is a super-2 number, since 2×20642431² = 852219915179522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20642731) 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, 448726 + ... + 448771.

It is an arithmetic number, because the mean of its divisors is an integer number (5384988).

Almost surely, 2^20642431 is an apocalyptic number.

20642431 is a deficient number, since it is larger than the sum of its proper divisors (897521).

20642431 is an equidigital number, since it uses as much as digits as its factorization.

20642431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 897520.

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 20642431 is about 4543.3942157819. The cubic root of 20642431 is about 274.3175629689.

The spelling of 20642431 in words is "twenty million, six hundred forty-two thousand, four hundred thirty-one".