20638780 has 24 divisors (see below), whose sum is σ = 43867152. Its totient is φ = 8155392.

The previous prime is 20638771. The next prime is 20638789. The reversal of 20638780 is 8783602.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (20638771) and next prime (20638789).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20638789) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 4557 + ... + 7876.

It is an arithmetic number, because the mean of its divisors is an integer number (1827798).

Almost surely, 2^20638780 is an apocalyptic number.

20638780 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

20638780 is an abundant number, since it is smaller than the sum of its proper divisors (23228372).

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

20638780 is a wasteful number, since it uses less digits than its factorization.

20638780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12525 (or 12523 counting only the distinct ones).

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 20638780 is about 4542.9924058928. The cubic root of 20638780 is about 274.3013892848.

The spelling of 20638780 in words is "twenty million, six hundred thirty-eight thousand, seven hundred eighty".