64855621 has 4 divisors (see below), whose sum is σ = 64976044. Its totient is φ = 64735200.

The previous prime is 64855613. The next prime is 64855633. The reversal of 64855621 is 12655846.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 43046721 + 21808900 = 6561^2 + 4670^2 .

It is a cyclic number.

It is not a de Polignac number, because 64855621 - 2³ = 64855613 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (64835621) 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, 59400 + ... + 60481.

It is an arithmetic number, because the mean of its divisors is an integer number (16244011).

Almost surely, 2^64855621 is an apocalyptic number.

It is an amenable number.

64855621 is a deficient number, since it is larger than the sum of its proper divisors (120423).

64855621 is a wasteful number, since it uses less digits than its factorization.

64855621 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 120422.

The product of its digits is 57600, while the sum is 37.

The square root of 64855621 is about 8053.2987651024. The cubic root of 64855621 is about 401.7746585733.

The spelling of 64855621 in words is "sixty-four million, eight hundred fifty-five thousand, six hundred twenty-one".