72686665 has 4 divisors (see below), whose sum is σ = 87224004. Its totient is φ = 58149328.

The previous prime is 72686657. The next prime is 72686671. The reversal of 72686665 is 56668627.

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

It can be written as a sum of positive squares in 2 ways, for example, as 11095561 + 61591104 = 3331^2 + 7848^2 .

It is a cyclic number.

It is not a de Polignac number, because 72686665 - 2³ = 72686657 is a prime.

It is a Duffinian number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7268662 + ... + 7268671.

It is an arithmetic number, because the mean of its divisors is an integer number (21806001).

Almost surely, 2^72686665 is an apocalyptic number.

It is an amenable number.

72686665 is a deficient number, since it is larger than the sum of its proper divisors (14537339).

72686665 is a wasteful number, since it uses less digits than its factorization.

72686665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14537338.

The product of its digits is 725760, while the sum is 46.

The square root of 72686665 is about 8525.6474827429. The cubic root of 72686665 is about 417.3351016715.

The spelling of 72686665 in words is "seventy-two million, six hundred eighty-six thousand, six hundred sixty-five".