656661001 has 4 divisors (see below), whose sum is σ = 657459712. Its totient is φ = 655862292.

The previous prime is 656660999. The next prime is 656661059. The reversal of 656661001 is 100166656.

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 656661001 - 2¹ = 656660999 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (656661101) 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, 398121 + ... + 399766.

It is an arithmetic number, because the mean of its divisors is an integer number (164364928).

Almost surely, 2^656661001 is an apocalyptic number.

It is an amenable number.

656661001 is a deficient number, since it is larger than the sum of its proper divisors (798711).

656661001 is an equidigital number, since it uses as much as digits as its factorization.

656661001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 798710.

The product of its (nonzero) digits is 6480, while the sum is 31.

The square root of 656661001 is about 25625.3975774036. The cubic root of 656661001 is about 869.1880392892.

The spelling of 656661001 in words is "six hundred fifty-six million, six hundred sixty-one thousand, one".