84520721 has 8 divisors (see below), whose sum is σ = 91140000. Its totient is φ = 78118560.

The previous prime is 84520693. The next prime is 84520727. The reversal of 84520721 is 12702548.

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 84520721 - 2²² = 80326417 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (84520727) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 53471 + ... + 55028.

It is an arithmetic number, because the mean of its divisors is an integer number (11392500).

Almost surely, 2^84520721 is an apocalyptic number.

It is an amenable number.

84520721 is a deficient number, since it is larger than the sum of its proper divisors (6619279).

84520721 is a wasteful number, since it uses less digits than its factorization.

84520721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 108559.

The product of its (nonzero) digits is 4480, while the sum is 29.

The square root of 84520721 is about 9193.5151601550. The cubic root of 84520721 is about 438.8550137563.

The spelling of 84520721 in words is "eighty-four million, five hundred twenty thousand, seven hundred twenty-one".