72663721 has 8 divisors (see below), whose sum is σ = 80777984. Its totient is φ = 64910160.

The previous prime is 72663713. The next prime is 72663769. The reversal of 72663721 is 12736627.

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 72663721 - 2³ = 72663713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72603721) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 89751 + ... + 90556.

It is an arithmetic number, because the mean of its divisors is an integer number (10097248).

Almost surely, 2^72663721 is an apocalyptic number.

It is an amenable number.

72663721 is a deficient number, since it is larger than the sum of its proper divisors (8114263).

72663721 is a wasteful number, since it uses less digits than its factorization.

72663721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 180351.

The product of its digits is 21168, while the sum is 34.

The square root of 72663721 is about 8524.3017895896. The cubic root of 72663721 is about 417.2911855728.

The spelling of 72663721 in words is "seventy-two million, six hundred sixty-three thousand, seven hundred twenty-one".