73291721 has 4 divisors (see below), whose sum is σ = 77149200. Its totient is φ = 69434244.

The previous prime is 73291711. The next prime is 73291727. The reversal of 73291721 is 12719237.

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.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-73291721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (73291727) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1928711 + ... + 1928748.

It is an arithmetic number, because the mean of its divisors is an integer number (19287300).

Almost surely, 2^73291721 is an apocalyptic number.

It is an amenable number.

73291721 is a deficient number, since it is larger than the sum of its proper divisors (3857479).

73291721 is a wasteful number, since it uses less digits than its factorization.

73291721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3857478.

The product of its digits is 5292, while the sum is 32.

The square root of 73291721 is about 8561.0584041928. The cubic root of 73291721 is about 418.4898924955.

The spelling of 73291721 in words is "seventy-three million, two hundred ninety-one thousand, seven hundred twenty-one".