72618931391 has 4 divisors (see below), whose sum is σ = 72619582992. Its totient is φ = 72618279792.

The previous prime is 72618931321. The next prime is 72618931397. The reversal of 72618931391 is 19313981627.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72618931391 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72618931397) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 111755 + ... + 397148.

It is an arithmetic number, because the mean of its divisors is an integer number (18154895748).

Almost surely, 2^72618931391 is an apocalyptic number.

72618931391 is a deficient number, since it is larger than the sum of its proper divisors (651601).

72618931391 is a wasteful number, since it uses less digits than its factorization.

72618931391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 651600.

The product of its digits is 489888, while the sum is 50.

Adding to 72618931391 its sum of digits (50), we get a square (72618931441 = 269479²).

The spelling of 72618931391 in words is "seventy-two billion, six hundred eighteen million, nine hundred thirty-one thousand, three hundred ninety-one".