16621551620 has 24 divisors (see below), whose sum is σ = 35426235264. Its totient is φ = 6549386976.

The previous prime is 16621551613. The next prime is 16621551629. The reversal of 16621551620 is 2615512661.

It is not an unprimeable number, because it can be changed into a prime (16621551629) 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, 6200732 + ... + 6203411.

It is an arithmetic number, because the mean of its divisors is an integer number (1476093136).

Almost surely, 2^16621551620 is an apocalyptic number.

16621551620 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

16621551620 is an abundant number, since it is smaller than the sum of its proper divisors (18804683644).

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

16621551620 is a wasteful number, since it uses less digits than its factorization.

16621551620 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12404219 (or 12404217 counting only the distinct ones).

The product of its (nonzero) digits is 21600, while the sum is 35.

The spelling of 16621551620 in words is "sixteen billion, six hundred twenty-one million, five hundred fifty-one thousand, six hundred twenty".