72913821 has 4 divisors (see below), whose sum is σ = 97218432. Its totient is φ = 48609212.

The previous prime is 72913817. The next prime is 72913843. The reversal of 72913821 is 12831927.

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 72913821 - 2² = 72913817 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72913871) 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, 12152301 + ... + 12152306.

It is an arithmetic number, because the mean of its divisors is an integer number (24304608).

Almost surely, 2^72913821 is an apocalyptic number.

It is an amenable number.

72913821 is a deficient number, since it is larger than the sum of its proper divisors (24304611).

72913821 is a wasteful number, since it uses less digits than its factorization.

72913821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24304610.

The product of its digits is 6048, while the sum is 33.

The square root of 72913821 is about 8538.9590114955. The cubic root of 72913821 is about 417.7693931097.

The spelling of 72913821 in words is "seventy-two million, nine hundred thirteen thousand, eight hundred twenty-one".