20515957 has 24 divisors (see below), whose sum is σ = 27578880. Its totient is φ = 15039360.

The previous prime is 20515933. The next prime is 20515967. The reversal of 20515957 is 75951502.

It is not a de Polignac number, because 20515957 - 2¹⁵ = 20483189 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20515907) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 8044 + ... + 10282.

It is an arithmetic number, because the mean of its divisors is an integer number (1149120).

Almost surely, 2^20515957 is an apocalyptic number.

It is an amenable number.

20515957 is a deficient number, since it is larger than the sum of its proper divisors (7062923).

20515957 is a wasteful number, since it uses less digits than its factorization.

20515957 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2281 (or 2274 counting only the distinct ones).

The product of its (nonzero) digits is 15750, while the sum is 34.

The square root of 20515957 is about 4529.4543821524. The cubic root of 20515957 is about 273.7561766154.

It can be divided in two parts, 2051 and 5957, that added together give a palindrome (8008).

The spelling of 20515957 in words is "twenty million, five hundred fifteen thousand, nine hundred fifty-seven".