72665779 has 4 divisors (see below), whose sum is σ = 73371376. Its totient is φ = 71960184.

The previous prime is 72665773. The next prime is 72665819. The reversal of 72665779 is 97756627.

It is a happy number.

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

It is a cyclic number.

It is not a de Polignac number, because 72665779 - 2³ = 72665771 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72665771) 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 in 3 ways as a sum of consecutive naturals, for example, 352644 + ... + 352849.

It is an arithmetic number, because the mean of its divisors is an integer number (18342844).

Almost surely, 2^72665779 is an apocalyptic number.

72665779 is a deficient number, since it is larger than the sum of its proper divisors (705597).

72665779 is a wasteful number, since it uses less digits than its factorization.

72665779 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 705596.

The product of its digits is 1111320, while the sum is 49.

The square root of 72665779 is about 8524.4225024338. The cubic root of 72665779 is about 417.2951250773.

The spelling of 72665779 in words is "seventy-two million, six hundred sixty-five thousand, seven hundred seventy-nine".