72781906 has 8 divisors (see below), whose sum is σ = 110962764. Its totient is φ = 35794320.

The previous prime is 72781889. The next prime is 72781921. The reversal of 72781906 is 60918727.

It can be written as a sum of positive squares in 2 ways, for example, as 48427681 + 24354225 = 6959^2 + 4935^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 298165 + ... + 298408.

Almost surely, 2^72781906 is an apocalyptic number.

72781906 is a deficient number, since it is larger than the sum of its proper divisors (38180858).

72781906 is a wasteful number, since it uses less digits than its factorization.

72781906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 596636.

The product of its (nonzero) digits is 42336, while the sum is 40.

The square root of 72781906 is about 8531.2312124335. The cubic root of 72781906 is about 417.5172995330.

The spelling of 72781906 in words is "seventy-two million, seven hundred eighty-one thousand, nine hundred six".