20644156 has 48 divisors (see below), whose sum is σ = 41686848. Its totient is φ = 8870400.

The previous prime is 20644153. The next prime is 20644157. The reversal of 20644156 is 65144602.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20644153) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 48826 + ... + 49246.

It is an arithmetic number, because the mean of its divisors is an integer number (868476).

Almost surely, 2^20644156 is an apocalyptic number.

20644156 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

20644156 is an abundant number, since it is smaller than the sum of its proper divisors (21042692).

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

20644156 is a wasteful number, since it uses less digits than its factorization.

20644156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 502 (or 500 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 28.

The square root of 20644156 is about 4543.5840478635. The cubic root of 20644156 is about 274.3252039394.

Adding to 20644156 its reverse (65144602), we get a palindrome (85788758).

The spelling of 20644156 in words is "twenty million, six hundred forty-four thousand, one hundred fifty-six".