656401 has 4 divisors (see below), whose sum is σ = 660592. Its totient is φ = 652212.

The previous prime is 656389. The next prime is 656407. The reversal of 656401 is 104656.

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 656401 - 2⁷ = 656273 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (656407) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1851 + ... + 2176.

It is an arithmetic number, because the mean of its divisors is an integer number (165148).

2⁶⁵⁶⁴⁰¹ is an apocalyptic number.

It is an amenable number.

656401 is a deficient number, since it is larger than the sum of its proper divisors (4191).

656401 is a wasteful number, since it uses less digits than its factorization.

656401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4190.

The product of its (nonzero) digits is 720, while the sum is 22.

The square root of 656401 is about 810.1857811638. The cubic root of 656401 is about 86.9073307542.

The spelling of 656401 in words is "six hundred fifty-six thousand, four hundred one".