72644421 has 4 divisors (see below), whose sum is σ = 96859232. Its totient is φ = 48429612.

The previous prime is 72644393. The next prime is 72644443. The reversal of 72644421 is 12444627.

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 not a de Polignac number, because 72644421 - 2¹⁷ = 72513349 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 (72644461) 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, 12107401 + ... + 12107406.

It is an arithmetic number, because the mean of its divisors is an integer number (24214808).

Almost surely, 2^72644421 is an apocalyptic number.

It is an amenable number.

72644421 is a deficient number, since it is larger than the sum of its proper divisors (24214811).

72644421 is a wasteful number, since it uses less digits than its factorization.

72644421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24214810.

The product of its digits is 10752, while the sum is 30.

The square root of 72644421 is about 8523.1696568824. The cubic root of 72644421 is about 417.2542371346.

The spelling of 72644421 in words is "seventy-two million, six hundred forty-four thousand, four hundred twenty-one".