72820521 has 12 divisors (see below), whose sum is σ = 110721520. Its totient is φ = 45991800.

The previous prime is 72820513. The next prime is 72820529. The reversal of 72820521 is 12502827.

It is an interprime number because it is at equal distance from previous prime (72820513) and next prime (72820529).

It is not a de Polignac number, because 72820521 - 2³ = 72820513 is a prime.

It is a super-2 number, since 2×72820521² = 10605656557422882, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72820529) 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 11 ways as a sum of consecutive naturals, for example, 212755 + ... + 213096.

Almost surely, 2^72820521 is an apocalyptic number.

It is an amenable number.

72820521 is a deficient number, since it is larger than the sum of its proper divisors (37900999).

72820521 is a wasteful number, since it uses less digits than its factorization.

72820521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 425876 (or 425873 counting only the distinct ones).

The product of its (nonzero) digits is 2240, while the sum is 27.

The square root of 72820521 is about 8533.4940674966. The cubic root of 72820521 is about 417.5911254830.

The spelling of 72820521 in words is "seventy-two million, eight hundred twenty thousand, five hundred twenty-one".