72781816 has 32 divisors (see below), whose sum is σ = 139920480. Its totient is φ = 35481600.

The previous prime is 72781783. The next prime is 72781829. The reversal of 72781816 is 61818727.

It is an alternating number because its digits alternate between odd and even.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 54436 + ... + 55756.

It is an arithmetic number, because the mean of its divisors is an integer number (4372515).

Almost surely, 2^72781816 is an apocalyptic number.

It is an amenable number.

72781816 is a deficient number, since it is larger than the sum of its proper divisors (67138664).

72781816 is a wasteful number, since it uses less digits than its factorization.

72781816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1495 (or 1491 counting only the distinct ones).

The product of its digits is 37632, while the sum is 40.

The square root of 72781816 is about 8531.2259376950. The cubic root of 72781816 is about 417.5171274363.

The spelling of 72781816 in words is "seventy-two million, seven hundred eighty-one thousand, eight hundred sixteen".