72978391 has 8 divisors (see below), whose sum is σ = 73787904. Its totient is φ = 72172800.

The previous prime is 72978377. The next prime is 72978419. The reversal of 72978391 is 19387927.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 72978391 - 2¹³ = 72970199 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 (72976391) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 50211 + ... + 51643.

It is an arithmetic number, because the mean of its divisors is an integer number (9223488).

Almost surely, 2^72978391 is an apocalyptic number.

72978391 is a deficient number, since it is larger than the sum of its proper divisors (809513).

72978391 is a wasteful number, since it uses less digits than its factorization.

72978391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1961.

The product of its digits is 190512, while the sum is 46.

The square root of 72978391 is about 8542.7390806462. The cubic root of 72978391 is about 417.8926775133.

The spelling of 72978391 in words is "seventy-two million, nine hundred seventy-eight thousand, three hundred ninety-one".