20478957 has 4 divisors (see below), whose sum is σ = 27305280. Its totient is φ = 13652636.

The previous prime is 20478949. The next prime is 20478961. The reversal of 20478957 is 75987402.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 20478957 - 2³ = 20478949 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20478917) 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, 3413157 + ... + 3413162.

It is an arithmetic number, because the mean of its divisors is an integer number (6826320).

Almost surely, 2^20478957 is an apocalyptic number.

It is an amenable number.

20478957 is a deficient number, since it is larger than the sum of its proper divisors (6826323).

20478957 is an equidigital number, since it uses as much as digits as its factorization.

20478957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6826322.

The product of its (nonzero) digits is 141120, while the sum is 42.

The square root of 20478957 is about 4525.3681618184. The cubic root of 20478957 is about 273.5915068454.

The spelling of 20478957 in words is "twenty million, four hundred seventy-eight thousand, nine hundred fifty-seven".