72978013 has 4 divisors (see below), whose sum is σ = 73007680. Its totient is φ = 72948348.

The previous prime is 72978001. The next prime is 72978019. The reversal of 72978013 is 31087927.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 72978013 - 2¹⁷ = 72846941 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72978019) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10773 + ... + 16186.

It is an arithmetic number, because the mean of its divisors is an integer number (18251920).

Almost surely, 2^72978013 is an apocalyptic number.

It is an amenable number.

72978013 is a deficient number, since it is larger than the sum of its proper divisors (29667).

72978013 is a wasteful number, since it uses less digits than its factorization.

72978013 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29666.

The product of its (nonzero) digits is 21168, while the sum is 37.

The square root of 72978013 is about 8542.7169565660. The cubic root of 72978013 is about 417.8919560043.

It can be divided in two parts, 7 and 2978013, that added together give a triangular number (2978020 = T₂₄₄₀).

The spelling of 72978013 in words is "seventy-two million, nine hundred seventy-eight thousand, thirteen".