72021920 has 24 divisors (see below), whose sum is σ = 170152164. Its totient is φ = 28808704.

The previous prime is 72021889. The next prime is 72021967. The reversal of 72021920 is 2912027.

It can be written as a sum of positive squares in 2 ways, for example, as 63425296 + 8596624 = 7964^2 + 2932^2 .

It is an unprimeable number.

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, 224909 + ... + 225228.

Almost surely, 2^72021920 is an apocalyptic number.

It is an amenable number.

72021920 is an abundant number, since it is smaller than the sum of its proper divisors (98130244).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

72021920 is a wasteful number, since it uses less digits than its factorization.

72021920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 450152 (or 450144 counting only the distinct ones).

The product of its (nonzero) digits is 504, while the sum is 23.

The square root of 72021920 is about 8486.5729243317. The cubic root of 72021920 is about 416.0589783244.

Adding to 72021920 its reverse (2912027), we get a palindrome (74933947).

The spelling of 72021920 in words is "seventy-two million, twenty-one thousand, nine hundred twenty".