72720171816 has 128 divisors (see below), whose sum is σ = 194793984000. Its totient is φ = 22556282112.

The previous prime is 72720171787. The next prime is 72720171919. The reversal of 72720171816 is 61817102727.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 7091605 + ... + 7101851.

It is an arithmetic number, because the mean of its divisors is an integer number (1521828000).

Almost surely, 2^72720171816 is an apocalyptic number.

72720171816 is a gapful number since it is divisible by the number (76) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 72720171816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (97396992000).

72720171816 is an abundant number, since it is smaller than the sum of its proper divisors (122073812184).

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

72720171816 is a wasteful number, since it uses less digits than its factorization.

72720171816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10551 (or 10547 counting only the distinct ones).

The product of its (nonzero) digits is 65856, while the sum is 42.

The spelling of 72720171816 in words is "seventy-two billion, seven hundred twenty million, one hundred seventy-one thousand, eight hundred sixteen".