20957431 has 8 divisors (see below), whose sum is σ = 22896144. Its totient is φ = 19024320.

The previous prime is 20957407. The next prime is 20957473. The reversal of 20957431 is 13475902.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 20957431 - 2⁷ = 20957303 is a prime.

It is a super-2 number, since 2×20957431² = 878427828239522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20957393 and 20957402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20957491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12325 + ... + 13921.

It is an arithmetic number, because the mean of its divisors is an integer number (2862018).

Almost surely, 2^20957431 is an apocalyptic number.

20957431 is a deficient number, since it is larger than the sum of its proper divisors (1938713).

20957431 is a wasteful number, since it uses less digits than its factorization.

20957431 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2801.

The product of its (nonzero) digits is 7560, while the sum is 31.

The square root of 20957431 is about 4577.9286800910. The cubic root of 20957431 is about 275.7058714636.

The spelling of 20957431 in words is "twenty million, nine hundred fifty-seven thousand, four hundred thirty-one".