16620621990 has 32 divisors (see below), whose sum is σ = 45587992320. Its totient is φ = 3798999264.

The previous prime is 16620621989. The next prime is 16620622003. The reversal of 16620621990 is 9912602661.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 39572700 + ... + 39573119.

It is an arithmetic number, because the mean of its divisors is an integer number (1424624760).

Almost surely, 2^16620621990 is an apocalyptic number.

16620621990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

16620621990 is an abundant number, since it is smaller than the sum of its proper divisors (28967370330).

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

16620621990 is a wasteful number, since it uses less digits than its factorization.

16620621990 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 79145836.

The product of its (nonzero) digits is 69984, while the sum is 42.

The spelling of 16620621990 in words is "sixteen billion, six hundred twenty million, six hundred twenty-one thousand, nine hundred ninety".