72972721 has 16 divisors (see below), whose sum is σ = 81126144. Its totient is φ = 65286144.

The previous prime is 72972709. The next prime is 72972727. The reversal of 72972721 is 12727927.

It is not a de Polignac number, because 72972721 - 2⁹ = 72972209 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72972727) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 74980 + ... + 75946.

It is an arithmetic number, because the mean of its divisors is an integer number (5070384).

Almost surely, 2^72972721 is an apocalyptic number.

It is an amenable number.

72972721 is a deficient number, since it is larger than the sum of its proper divisors (8153423).

72972721 is a wasteful number, since it uses less digits than its factorization.

72972721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1200.

The product of its digits is 24696, while the sum is 37.

The square root of 72972721 is about 8542.4072134264. The cubic root of 72972721 is about 417.8818546162.

The spelling of 72972721 in words is "seventy-two million, nine hundred seventy-two thousand, seven hundred twenty-one".