72321639 has 16 divisors (see below), whose sum is σ = 104294400. Its totient is φ = 44313696.

The previous prime is 72321631. The next prime is 72321659. The reversal of 72321639 is 93612327.

It is a happy number.

It is not a de Polignac number, because 72321639 - 2³ = 72321631 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72321631) 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, 5442 + ... + 13200.

It is an arithmetic number, because the mean of its divisors is an integer number (6518400).

Almost surely, 2^72321639 is an apocalyptic number.

72321639 is a deficient number, since it is larger than the sum of its proper divisors (31972761).

72321639 is a wasteful number, since it uses less digits than its factorization.

72321639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8014.

The product of its digits is 13608, while the sum is 33.

The square root of 72321639 is about 8504.2130147357. The cubic root of 72321639 is about 416.6353222999.

The spelling of 72321639 in words is "seventy-two million, three hundred twenty-one thousand, six hundred thirty-nine".