20256840 has 48 divisors (see below), whose sum is σ = 65835900. Its totient is φ = 5401728.

The previous prime is 20256823. The next prime is 20256851. The reversal of 20256840 is 4865202.

It can be written as a sum of positive squares in 2 ways, for example, as 18714276 + 1542564 = 4326^2 + 1242^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 27775 + ... + 28494.

Almost surely, 2^20256840 is an apocalyptic number.

20256840 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20256840 is an abundant number, since it is smaller than the sum of its proper divisors (45579060).

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

20256840 is a wasteful number, since it uses less digits than its factorization.

20256840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56286 (or 56279 counting only the distinct ones).

The product of its (nonzero) digits is 3840, while the sum is 27.

The square root of 20256840 is about 4500.7599358331. The cubic root of 20256840 is about 272.5987746179.

The spelling of 20256840 in words is "twenty million, two hundred fifty-six thousand, eight hundred forty".