72978806 has 4 divisors (see below), whose sum is σ = 109468212. Its totient is φ = 36489402.

The previous prime is 72978799. The next prime is 72978809. The reversal of 72978806 is 60887927.

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

It is a super-2 number, since 2×72978806² = 10651812250371272, which contains 22 as substring.

It is a Curzon number.

It is a plaindrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72978809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 18244700 + ... + 18244703.

It is an arithmetic number, because the mean of its divisors is an integer number (27367053).

Almost surely, 2^72978806 is an apocalyptic number.

72978806 is a deficient number, since it is larger than the sum of its proper divisors (36489406).

72978806 is a wasteful number, since it uses less digits than its factorization.

72978806 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 36489405.

The product of its (nonzero) digits is 338688, while the sum is 47.

The square root of 72978806 is about 8542.7633702450. The cubic root of 72978806 is about 417.8934696434.

The spelling of 72978806 in words is "seventy-two million, nine hundred seventy-eight thousand, eight hundred six".