655921 has 4 divisors (see below), whose sum is σ = 749632. Its totient is φ = 562212.

The previous prime is 655913. The next prime is 655927. The reversal of 655921 is 129556.

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 not a de Polignac number, because 655921 - 2³ = 655913 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 655921.

It is not an unprimeable number, because it can be changed into a prime (655927) 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, 46845 + ... + 46858.

It is an arithmetic number, because the mean of its divisors is an integer number (187408).

2⁶⁵⁵⁹²¹ is an apocalyptic number.

It is an amenable number.

655921 is a deficient number, since it is larger than the sum of its proper divisors (93711).

655921 is an equidigital number, since it uses as much as digits as its factorization.

655921 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93710.

The product of its digits is 2700, while the sum is 28.

The square root of 655921 is about 809.8894986355. The cubic root of 655921 is about 86.8861416278.

The spelling of 655921 in words is "six hundred fifty-five thousand, nine hundred twenty-one".