20557156 has 9 divisors (see below), whose sum is σ = 35990899. Its totient is φ = 10274044.

The previous prime is 20557153. The next prime is 20557157. The reversal of 20557156 is 65175502.

The square root of 20557156 is 4534.

It is a perfect power (a square), and thus also a powerful number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (20557153) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 7935 + ... + 10201.

Almost surely, 2^20557156 is an apocalyptic number.

20557156 is the 4534-th square number.

It is an amenable number.

20557156 is a deficient number, since it is larger than the sum of its proper divisors (15433743).

20557156 is an frugal number, since it uses more digits than its factorization.

20557156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4538 (or 2269 counting only the distinct ones).

The product of its (nonzero) digits is 10500, while the sum is 31.

The cubic root of 20557156 is about 273.9393013822.

The spelling of 20557156 in words is "twenty million, five hundred fifty-seven thousand, one hundred fifty-six".