16621900 has 18 divisors (see below), whose sum is σ = 36069740. Its totient is φ = 6648720.

The previous prime is 16621897. The next prime is 16621949. The reversal of 16621900 is 912661.

It is a super-2 number, since 2×16621900² = 552575119220000, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (25).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 83010 + ... + 83209.

Almost surely, 2^16621900 is an apocalyptic number.

16621900 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16621900 is an abundant number, since it is smaller than the sum of its proper divisors (19447840).

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

16621900 is a wasteful number, since it uses less digits than its factorization.

16621900 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 166233 (or 166226 counting only the distinct ones).

The product of its (nonzero) digits is 648, while the sum is 25.

The square root of 16621900 is about 4076.9964434618. The cubic root of 16621900 is about 255.2075716022.

The spelling of 16621900 in words is "sixteen million, six hundred twenty-one thousand, nine hundred".