664316261 has 4 divisors (see below), whose sum is σ = 759218592. Its totient is φ = 569413932.

The previous prime is 664316251. The next prime is 664316297. The reversal of 664316261 is 162613466.

664316261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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-664316261 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664316221) 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, 47451155 + ... + 47451168.

It is an arithmetic number, because the mean of its divisors is an integer number (189804648).

Almost surely, 2^664316261 is an apocalyptic number.

It is an amenable number.

664316261 is a deficient number, since it is larger than the sum of its proper divisors (94902331).

664316261 is an equidigital number, since it uses as much as digits as its factorization.

664316261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 94902330.

The product of its digits is 31104, while the sum is 35.

The square root of 664316261 is about 25774.3333764425. Note that the first 4 decimals coincide. The cubic root of 664316261 is about 872.5526216268.

The spelling of 664316261 in words is "six hundred sixty-four million, three hundred sixteen thousand, two hundred sixty-one".