20949156 has 18 divisors (see below), whose sum is σ = 52954902. Its totient is φ = 6983040.

The previous prime is 20949109. The next prime is 20949157. The reversal of 20949156 is 65194902.

It can be written as a sum of positive squares in only one way, i.e., 19980900 + 968256 = 4470^2 + 984^2 .

It is a tau number, because it is divible by the number of its divisors (18).

It is a super-2 number, since 2×20949156² = 877734274224672, which contains 22 as substring.

It is a Smith number, since the sum of its digits (36) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (36), and also a Moran number because the ratio is a prime number: 581921 = 20949156 / (2 + 0 + 9 + 4 + 9 + 1 + 5 + 6).

It is a self number, because there is not a number n which added to its sum of digits gives 20949156.

It is not an unprimeable number, because it can be changed into a prime (20949157) 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 5 ways as a sum of consecutive naturals, for example, 290925 + ... + 290996.

It is an arithmetic number, because the mean of its divisors is an integer number (2941939).

Almost surely, 2^20949156 is an apocalyptic number.

It is an amenable number.

20949156 is an abundant number, since it is smaller than the sum of its proper divisors (32005746).

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

20949156 is a wasteful number, since it uses less digits than its factorization.

20949156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 581931 (or 581926 counting only the distinct ones).

The product of its (nonzero) digits is 19440, while the sum is 36.

The square root of 20949156 is about 4577.0247978354. The cubic root of 20949156 is about 275.6695793814.

The spelling of 20949156 in words is "twenty million, nine hundred forty-nine thousand, one hundred fifty-six".