72997945 has 4 divisors (see below), whose sum is σ = 87597540. Its totient is φ = 58398352.

The previous prime is 72997933. The next prime is 72997973. The reversal of 72997945 is 54979927.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54979927 = 109 ⋅504403.

It can be written as a sum of positive squares in 2 ways, for example, as 45319824 + 27678121 = 6732^2 + 5261^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-72997945 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 72997892 and 72997901.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7299790 + ... + 7299799.

It is an arithmetic number, because the mean of its divisors is an integer number (21899385).

Almost surely, 2^72997945 is an apocalyptic number.

It is an amenable number.

72997945 is a deficient number, since it is larger than the sum of its proper divisors (14599595).

72997945 is a wasteful number, since it uses less digits than its factorization.

72997945 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14599594.

The product of its digits is 1428840, while the sum is 52.

The square root of 72997945 is about 8543.8834846924. The cubic root of 72997945 is about 417.9299978926.

The spelling of 72997945 in words is "seventy-two million, nine hundred ninety-seven thousand, nine hundred forty-five".