20491156 has 12 divisors (see below), whose sum is σ = 40982368. Its totient is φ = 8781912.

The previous prime is 20491147. The next prime is 20491157. The reversal of 20491156 is 65119402.

20491156 is an admirable number.

It is a Harshad number since it is a multiple of its sum of digits (28), and also a Moran number because the ratio is a prime number: 731827 = 20491156 / (2 + 0 + 4 + 9 + 1 + 1 + 5 + 6).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20491157) 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, 365886 + ... + 365941.

Almost surely, 2^20491156 is an apocalyptic number.

It is an amenable number.

20491156 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

20491156 is a wasteful number, since it uses less digits than its factorization.

20491156 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 731838 (or 731836 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 28.

The square root of 20491156 is about 4526.7158072934. The cubic root of 20491156 is about 273.6458208143.

The spelling of 20491156 in words is "twenty million, four hundred ninety-one thousand, one hundred fifty-six".