20863990 has 32 divisors (see below), whose sum is σ = 44789760. Its totient is φ = 6841824.

The previous prime is 20863949. The next prime is 20863991. The reversal of 20863990 is 9936802.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20863991) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4870 + ... + 8089.

It is an arithmetic number, because the mean of its divisors is an integer number (1399680).

Almost surely, 2^20863990 is an apocalyptic number.

20863990 is an abundant number, since it is smaller than the sum of its proper divisors (23925770).

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

20863990 is a wasteful number, since it uses less digits than its factorization.

20863990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12996.

The product of its (nonzero) digits is 23328, while the sum is 37.

The square root of 20863990 is about 4567.7116809186. The cubic root of 20863990 is about 275.2955060366.

The spelling of 20863990 in words is "twenty million, eight hundred sixty-three thousand, nine hundred ninety".