72979561 has 8 divisors (see below), whose sum is σ = 73611720. Its totient is φ = 72350592.

The previous prime is 72979547. The next prime is 72979591. The reversal of 72979561 is 16597927.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 16353936 + 56625625 = 4044^2 + 7525^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 72979561 - 2⁷ = 72979433 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72979541) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 67735 + ... + 68803.

It is an arithmetic number, because the mean of its divisors is an integer number (9201465).

Almost surely, 2^72979561 is an apocalyptic number.

It is an amenable number.

72979561 is a deficient number, since it is larger than the sum of its proper divisors (632159).

72979561 is a wasteful number, since it uses less digits than its factorization.

72979561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1595.

The product of its digits is 238140, while the sum is 46.

The square root of 72979561 is about 8542.8075595790. The cubic root of 72979561 is about 417.8949107398.

The spelling of 72979561 in words is "seventy-two million, nine hundred seventy-nine thousand, five hundred sixty-one".