72787978 has 4 divisors (see below), whose sum is σ = 109181970. Its totient is φ = 36393988.

The previous prime is 72787943. The next prime is 72788017. The reversal of 72787978 is 87978727.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 53978409 + 18809569 = 7347^2 + 4337^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 18196993 + ... + 18196996.

Almost surely, 2^72787978 is an apocalyptic number.

72787978 is a deficient number, since it is larger than the sum of its proper divisors (36393992).

72787978 is a wasteful number, since it uses less digits than its factorization.

72787978 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36393991.

The product of its digits is 2765952, while the sum is 55.

The square root of 72787978 is about 8531.5870739271. The cubic root of 72787978 is about 417.5289099944.

The spelling of 72787978 in words is "seventy-two million, seven hundred eighty-seven thousand, nine hundred seventy-eight".