20731256 has 32 divisors (see below), whose sum is σ = 47843040. Its totient is φ = 8201088.

The previous prime is 20731253. The next prime is 20731267. The reversal of 20731256 is 65213702.

It is a Harshad number since it is a multiple of its sum of digits (26).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20731253) 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 7 ways as a sum of consecutive naturals, for example, 13511 + ... + 14966.

It is an arithmetic number, because the mean of its divisors is an integer number (1495095).

Almost surely, 2^20731256 is an apocalyptic number.

20731256 is a gapful number since it is divisible by the number (26) formed by its first and last digit.

It is an amenable number.

20731256 is an abundant number, since it is smaller than the sum of its proper divisors (27111784).

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

20731256 is a wasteful number, since it uses less digits than its factorization.

20731256 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28503 (or 28499 counting only the distinct ones).

The product of its (nonzero) digits is 2520, while the sum is 26.

The square root of 20731256 is about 4553.1589034428. The cubic root of 20731256 is about 274.7104655178.

Adding to 20731256 its reverse (65213702), we get a palindrome (85944958).

The spelling of 20731256 in words is "twenty million, seven hundred thirty-one thousand, two hundred fifty-six".