72973221 has 4 divisors (see below), whose sum is σ = 97297632. Its totient is φ = 48648812.

The previous prime is 72973183. The next prime is 72973223. The reversal of 72973221 is 12237927.

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.

It is a cyclic number.

It is not a de Polignac number, because 72973221 - 2⁹ = 72972709 is a prime.

It is a super-2 number, since 2×72973221² = 10650181966229682, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72973223) 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, 12162201 + ... + 12162206.

It is an arithmetic number, because the mean of its divisors is an integer number (24324408).

Almost surely, 2^72973221 is an apocalyptic number.

It is an amenable number.

72973221 is a deficient number, since it is larger than the sum of its proper divisors (24324411).

72973221 is a wasteful number, since it uses less digits than its factorization.

72973221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24324410.

The product of its digits is 10584, while the sum is 33.

The square root of 72973221 is about 8542.4364791317. The cubic root of 72973221 is about 417.8828090389.

The spelling of 72973221 in words is "seventy-two million, nine hundred seventy-three thousand, two hundred twenty-one".