73657721 has 2 divisors, whose sum is σ = 73657722. Its totient is φ = 73657720.

The previous prime is 73657697. The next prime is 73657729. The reversal of 73657721 is 12775637.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70644025 + 3013696 = 8405^2 + 1736^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-73657721 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (73657729) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 36828860 + 36828861.

It is an arithmetic number, because the mean of its divisors is an integer number (36828861).

Almost surely, 2^73657721 is an apocalyptic number.

It is an amenable number.

73657721 is a deficient number, since it is larger than the sum of its proper divisors (1).

73657721 is an equidigital number, since it uses as much as digits as its factorization.

73657721 is an evil number, because the sum of its binary digits is even.

The product of its digits is 61740, while the sum is 38.

The square root of 73657721 is about 8582.4076458765. The cubic root of 73657721 is about 419.1853464257.

The spelling of 73657721 in words is "seventy-three million, six hundred fifty-seven thousand, seven hundred twenty-one".