72640421 has 8 divisors (see below), whose sum is σ = 84069120. Its totient is φ = 61474608.

The previous prime is 72640349. The next prime is 72640429. The reversal of 72640421 is 12404627.

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 72640421 - 2¹⁴ = 72624037 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72640429) 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 7 ways as a sum of consecutive naturals, for example, 65126 + ... + 66231.

It is an arithmetic number, because the mean of its divisors is an integer number (10508640).

Almost surely, 2^72640421 is an apocalyptic number.

It is an amenable number.

72640421 is a deficient number, since it is larger than the sum of its proper divisors (11428699).

72640421 is a wasteful number, since it uses less digits than its factorization.

72640421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131443.

The product of its (nonzero) digits is 2688, while the sum is 26.

The square root of 72640421 is about 8522.9349991655. The cubic root of 72640421 is about 417.2465786085.

The spelling of 72640421 in words is "seventy-two million, six hundred forty thousand, four hundred twenty-one".