72663421 has 4 divisors (see below), whose sum is σ = 74353312. Its totient is φ = 70973532.

The previous prime is 72663401. The next prime is 72663499. The reversal of 72663421 is 12436627.

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 72663421 - 2¹⁵ = 72630653 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 (72663401) 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, 844881 + ... + 844966.

It is an arithmetic number, because the mean of its divisors is an integer number (18588328).

Almost surely, 2^72663421 is an apocalyptic number.

It is an amenable number.

72663421 is a deficient number, since it is larger than the sum of its proper divisors (1689891).

72663421 is a wasteful number, since it uses less digits than its factorization.

72663421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1689890.

The product of its digits is 12096, while the sum is 31.

The square root of 72663421 is about 8524.2841928223. The cubic root of 72663421 is about 417.2906112948.

The spelling of 72663421 in words is "seventy-two million, six hundred sixty-three thousand, four hundred twenty-one".