72806391 has 32 divisors (see below), whose sum is σ = 123886080. Its totient is φ = 41395968.

The previous prime is 72806389. The next prime is 72806411. The reversal of 72806391 is 19360827.

It is not a de Polignac number, because 72806391 - 2¹ = 72806389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72806381) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 42055 + ... + 43751.

It is an arithmetic number, because the mean of its divisors is an integer number (3871440).

Almost surely, 2^72806391 is an apocalyptic number.

72806391 is a deficient number, since it is larger than the sum of its proper divisors (51079689).

72806391 is a wasteful number, since it uses less digits than its factorization.

72806391 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1940 (or 1934 counting only the distinct ones).

The product of its (nonzero) digits is 18144, while the sum is 36.

The square root of 72806391 is about 8532.6661132380. Note that the first 3 decimals coincide. The cubic root of 72806391 is about 417.5641141213.

The spelling of 72806391 in words is "seventy-two million, eight hundred six thousand, three hundred ninety-one".