657949609 has 4 divisors (see below), whose sum is σ = 658913616. Its totient is φ = 656985604.

The previous prime is 657949603. The next prime is 657949631. The reversal of 657949609 is 906949756.

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 a de Polignac number, because none of the positive numbers 2^k-657949609 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 657949609.

It is not an unprimeable number, because it can be changed into a prime (657949603) 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, 480979 + ... + 482344.

It is an arithmetic number, because the mean of its divisors is an integer number (164728404).

Almost surely, 2^657949609 is an apocalyptic number.

It is an amenable number.

657949609 is a deficient number, since it is larger than the sum of its proper divisors (964007).

657949609 is an equidigital number, since it uses as much as digits as its factorization.

657949609 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 964006.

The product of its (nonzero) digits is 3674160, while the sum is 55.

The square root of 657949609 is about 25650.5284351025. The cubic root of 657949609 is about 869.7562222700.

The spelling of 657949609 in words is "six hundred fifty-seven million, nine hundred forty-nine thousand, six hundred nine".