655595921 has 4 divisors (see below), whose sum is σ = 655925232. Its totient is φ = 655266612.

The previous prime is 655595917. The next prime is 655595929. The reversal of 655595921 is 129595556.

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 not a de Polignac number, because 655595921 - 2² = 655595917 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (655595929) 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, 161651 + ... + 165656.

It is an arithmetic number, because the mean of its divisors is an integer number (163981308).

Almost surely, 2^655595921 is an apocalyptic number.

It is an amenable number.

655595921 is a deficient number, since it is larger than the sum of its proper divisors (329311).

655595921 is a wasteful number, since it uses less digits than its factorization.

655595921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329310.

The product of its digits is 607500, while the sum is 47.

The square root of 655595921 is about 25604.6074174161. The cubic root of 655595921 is about 868.7178546427.

The spelling of 655595921 in words is "six hundred fifty-five million, five hundred ninety-five thousand, nine hundred twenty-one".