73521721 has 8 divisors (see below), whose sum is σ = 90488384. Its totient is φ = 58170960.

The previous prime is 73521691. The next prime is 73521727. The reversal of 73521721 is 12712537.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 73521721 - 2⁵ = 73521689 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 73521721.

It is not an unprimeable number, because it can be changed into a prime (73521727) 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 7 ways as a sum of consecutive naturals, for example, 403875 + ... + 404056.

It is an arithmetic number, because the mean of its divisors is an integer number (11311048).

Almost surely, 2^73521721 is an apocalyptic number.

It is an amenable number.

73521721 is a deficient number, since it is larger than the sum of its proper divisors (16966663).

73521721 is a wasteful number, since it uses less digits than its factorization.

73521721 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 807951.

The product of its digits is 2940, while the sum is 28.

The square root of 73521721 is about 8574.4808006083. The cubic root of 73521721 is about 418.9271959371.

The spelling of 73521721 in words is "seventy-three million, five hundred twenty-one thousand, seven hundred twenty-one".