72352721 has 4 divisors (see below), whose sum is σ = 82688832. Its totient is φ = 62016612.

The previous prime is 72352699. The next prime is 72352751. The reversal of 72352721 is 12725327.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 12725327 = 2729 ⋅4663.

It is not a de Polignac number, because 72352721 - 2²² = 68158417 is a prime.

It is a super-2 number, since 2×72352721² = 10469832472207682, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72352751) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5168045 + ... + 5168058.

It is an arithmetic number, because the mean of its divisors is an integer number (20672208).

Almost surely, 2^72352721 is an apocalyptic number.

It is an amenable number.

72352721 is a deficient number, since it is larger than the sum of its proper divisors (10336111).

72352721 is a wasteful number, since it uses less digits than its factorization.

72352721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10336110.

The product of its digits is 5880, while the sum is 29.

The square root of 72352721 is about 8506.0402655995. The cubic root of 72352721 is about 416.6950001710.

The spelling of 72352721 in words is "seventy-two million, three hundred fifty-two thousand, seven hundred twenty-one".