72781818 has 16 divisors (see below), whose sum is σ = 153225120. Its totient is φ = 22983696.

The previous prime is 72781783. The next prime is 72781829. The reversal of 72781818 is 81818727.

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

It is a self number, because there is not a number n which added to its sum of digits gives 72781818.

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, 319105 + ... + 319332.

It is an arithmetic number, because the mean of its divisors is an integer number (9576570).

Almost surely, 2^72781818 is an apocalyptic number.

72781818 is an abundant number, since it is smaller than the sum of its proper divisors (80443302).

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

72781818 is a wasteful number, since it uses less digits than its factorization.

72781818 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 638461.

The product of its digits is 50176, while the sum is 42.

The square root of 72781818 is about 8531.2260549115. The cubic root of 72781818 is about 417.5171312607.

The spelling of 72781818 in words is "seventy-two million, seven hundred eighty-one thousand, eight hundred eighteen".