72961821 has 12 divisors (see below), whose sum is σ = 106833948. Its totient is φ = 47974464.

The previous prime is 72961789. The next prime is 72961829. The reversal of 72961821 is 12816927.

It can be written as a sum of positive squares in 2 ways, for example, as 49196196 + 23765625 = 7014^2 + 4875^2 .

It is not a de Polignac number, because 72961821 - 2⁵ = 72961789 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72961829) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 54870 + ... + 56183.

It is an arithmetic number, because the mean of its divisors is an integer number (8902829).

Almost surely, 2^72961821 is an apocalyptic number.

It is an amenable number.

72961821 is a deficient number, since it is larger than the sum of its proper divisors (33872127).

72961821 is a wasteful number, since it uses less digits than its factorization.

72961821 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111132 (or 111129 counting only the distinct ones).

The product of its digits is 12096, while the sum is 36.

The square root of 72961821 is about 8541.7691961326. The cubic root of 72961821 is about 417.8610471192.

The spelling of 72961821 in words is "seventy-two million, nine hundred sixty-one thousand, eight hundred twenty-one".