72912491 has 4 divisors (see below), whose sum is σ = 72972672. Its totient is φ = 72852312.

The previous prime is 72912487. The next prime is 72912493. The reversal of 72912491 is 19421927.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19421927 = 7 ⋅2774561.

It is a cyclic number.

It is not a de Polignac number, because 72912491 - 2² = 72912487 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (72912493) 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, 28235 + ... + 30708.

It is an arithmetic number, because the mean of its divisors is an integer number (18243168).

Almost surely, 2^72912491 is an apocalyptic number.

72912491 is a deficient number, since it is larger than the sum of its proper divisors (60181).

72912491 is a wasteful number, since it uses less digits than its factorization.

72912491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 60180.

The product of its digits is 9072, while the sum is 35.

The square root of 72912491 is about 8538.8811327949. The cubic root of 72912491 is about 417.7668529573.

The spelling of 72912491 in words is "seventy-two million, nine hundred twelve thousand, four hundred ninety-one".