72977281 has 4 divisors (see below), whose sum is σ = 78590932. Its totient is φ = 67363632.

The previous prime is 72977269. The next prime is 72977287. The reversal of 72977281 is 18277927.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 41796225 + 31181056 = 6465^2 + 5584^2 .

It is a cyclic number.

It is not a de Polignac number, because 72977281 - 2⁵ = 72977249 is a prime.

It is a super-2 number, since 2×72977281² = 10651367084305922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72977287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2806806 + ... + 2806831.

It is an arithmetic number, because the mean of its divisors is an integer number (19647733).

Almost surely, 2^72977281 is an apocalyptic number.

It is an amenable number.

72977281 is a deficient number, since it is larger than the sum of its proper divisors (5613651).

72977281 is a wasteful number, since it uses less digits than its factorization.

72977281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5613650.

The product of its digits is 98784, while the sum is 43.

The square root of 72977281 is about 8542.6741129461. The cubic root of 72977281 is about 417.8905587892.

The spelling of 72977281 in words is "seventy-two million, nine hundred seventy-seven thousand, two hundred eighty-one".