20620640 has 24 divisors (see below), whose sum is σ = 48716640. Its totient is φ = 8248192.

The previous prime is 20620637. The next prime is 20620651. The reversal of 20620640 is 4602602.

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent number.

It is an unprimeable number.

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 3 ways as a sum of consecutive naturals, for example, 64280 + ... + 64599.

It is an arithmetic number, because the mean of its divisors is an integer number (2029860).

Almost surely, 2^20620640 is an apocalyptic number.

20620640 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20620640 is an abundant number, since it is smaller than the sum of its proper divisors (28096000).

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

20620640 is a wasteful number, since it uses less digits than its factorization.

20620640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128894 (or 128886 counting only the distinct ones).

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 20620640 is about 4540.9954855736. The cubic root of 20620640 is about 274.2210020121.

The spelling of 20620640 in words is "twenty million, six hundred twenty thousand, six hundred forty".