657961 has 4 divisors (see below), whose sum is σ = 686592. Its totient is φ = 629332.

The previous prime is 657959. The next prime is 657973. The reversal of 657961 is 169756.

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 657961 - 2¹ = 657959 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (657911) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14281 + ... + 14326.

It is an arithmetic number, because the mean of its divisors is an integer number (171648).

2⁶⁵⁷⁹⁶¹ is an apocalyptic number.

It is an amenable number.

657961 is a deficient number, since it is larger than the sum of its proper divisors (28631).

657961 is a wasteful number, since it uses less digits than its factorization.

657961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 28630.

The product of its digits is 11340, while the sum is 34.

The square root of 657961 is about 811.1479519792. The cubic root of 657961 is about 86.9761241568.

The spelling of 657961 in words is "six hundred fifty-seven thousand, nine hundred sixty-one".