16721717156172 has 96 divisors (see below), whose sum is σ = 49794803072000. Its totient is φ = 4753625222016.

The previous prime is 16721717156059. The next prime is 16721717156173. The reversal of 16721717156172 is 27165171712761.

16721717156172 is a `hidden beast` number, since 1 + 6 + 7 + 2 + 1 + 7 + 1 + 7 + 1 + 561 + 72 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (16721717156173) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 55424113 + ... + 55725000.

Almost surely, 2^{16721717156172} is an apocalyptic number.

16721717156172 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

16721717156172 is an abundant number, since it is smaller than the sum of its proper divisors (33073085915828).

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

16721717156172 is a wasteful number, since it uses less digits than its factorization.

16721717156172 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111149332 (or 111149324 counting only the distinct ones).

The product of its digits is 1728720, while the sum is 54.

The spelling of 16721717156172 in words is "sixteen trillion, seven hundred twenty-one billion, seven hundred seventeen million, one hundred fifty-six thousand, one hundred seventy-two".