16165500021 has 32 divisors (see below), whose sum is σ = 27261987840. Its totient is φ = 9371300400.

The previous prime is 16165500019. The next prime is 16165500031. The reversal of 16165500021 is 12000556161.

It is a happy number.

16165500021 is a `hidden beast` number, since 1 + 6 + 1 + 655 + 0 + 0 + 0 + 2 + 1 = 666.

It is not a de Polignac number, because 16165500021 - 2¹ = 16165500019 is a prime.

It is a super-2 number, since 2×16165500021² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (16165500031) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1176415 + ... + 1190076.

It is an arithmetic number, because the mean of its divisors is an integer number (851937120).

Almost surely, 2^16165500021 is an apocalyptic number.

16165500021 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

16165500021 is a deficient number, since it is larger than the sum of its proper divisors (11096487819).

16165500021 is a wasteful number, since it uses less digits than its factorization.

16165500021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2366534 (or 2366528 counting only the distinct ones).

The product of its (nonzero) digits is 1800, while the sum is 27.

The spelling of 16165500021 in words is "sixteen billion, one hundred sixty-five million, five hundred thousand, twenty-one".