72781794664 has 16 divisors (see below), whose sum is σ = 136521084420. Its totient is φ = 36376172160.

The previous prime is 72781794641. The next prime is 72781794667. The reversal of 72781794664 is 46649718727.

It can be written as a sum of positive squares in 2 ways, for example, as 71080892100 + 1700902564 = 266610^2 + 41242^2 .

It is not an unprimeable number, because it can be changed into a prime (72781794667) 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, 1819627 + ... + 1859194.

Almost surely, 2^72781794664 is an apocalyptic number.

It is an amenable number.

72781794664 is a deficient number, since it is larger than the sum of its proper divisors (63739289756).

72781794664 is a wasteful number, since it uses less digits than its factorization.

72781794664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3681300 (or 3681296 counting only the distinct ones).

The product of its digits is 28449792, while the sum is 61.

The spelling of 72781794664 in words is "seventy-two billion, seven hundred eighty-one million, seven hundred ninety-four thousand, six hundred sixty-four".