20957947 has 4 divisors (see below), whose sum is σ = 21524416. Its totient is φ = 20391480.

The previous prime is 20957941. The next prime is 20958001. The reversal of 20957947 is 74975902.

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 20957947 - 2⁷ = 20957819 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20957941) 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, 283179 + ... + 283252.

It is an arithmetic number, because the mean of its divisors is an integer number (5381104).

Almost surely, 2^20957947 is an apocalyptic number.

20957947 is a deficient number, since it is larger than the sum of its proper divisors (566469).

20957947 is an equidigital number, since it uses as much as digits as its factorization.

20957947 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 566468.

The product of its (nonzero) digits is 158760, while the sum is 43.

The square root of 20957947 is about 4577.9850371097. The cubic root of 20957947 is about 275.7081341943.

It can be divided in two parts, 20957 and 947, that added together give a square (21904 = 148²).

The spelling of 20957947 in words is "twenty million, nine hundred fifty-seven thousand, nine hundred forty-seven".