72991980 has 144 divisors (see below), whose sum is σ = 232587264. Its totient is φ = 18506880.

The previous prime is 72991973. The next prime is 72991981. The reversal of 72991980 is 8919927.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (72991981) by changing a digit.

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 47 ways as a sum of consecutive naturals, for example, 574677 + ... + 574803.

Almost surely, 2^72991980 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 72991980, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (116293632).

72991980 is an abundant number, since it is smaller than the sum of its proper divisors (159595284).

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

72991980 is a wasteful number, since it uses less digits than its factorization.

72991980 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 276 (or 271 counting only the distinct ones).

The product of its (nonzero) digits is 81648, while the sum is 45.

The square root of 72991980 is about 8543.5343974259. The cubic root of 72991980 is about 417.9186139176.

The spelling of 72991980 in words is "seventy-two million, nine hundred ninety-one thousand, nine hundred eighty".