72539661 has 4 divisors (see below), whose sum is σ = 96719552. Its totient is φ = 48359772.

The previous prime is 72539653. The next prime is 72539671. The reversal of 72539661 is 16693527.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 16693527 = 3 ⋅5564509.

It is not a de Polignac number, because 72539661 - 2³ = 72539653 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (72539611) 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 3 ways as a sum of consecutive naturals, for example, 12089941 + ... + 12089946.

It is an arithmetic number, because the mean of its divisors is an integer number (24179888).

Almost surely, 2^72539661 is an apocalyptic number.

It is an amenable number.

72539661 is a deficient number, since it is larger than the sum of its proper divisors (24179891).

72539661 is a wasteful number, since it uses less digits than its factorization.

72539661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24179890.

The product of its digits is 68040, while the sum is 39.

The square root of 72539661 is about 8517.0218386476. The cubic root of 72539661 is about 417.0535675251.

The spelling of 72539661 in words is "seventy-two million, five hundred thirty-nine thousand, six hundred sixty-one".