664091 has 2 divisors, whose sum is σ = 664092. Its totient is φ = 664090.

The previous prime is 664067. The next prime is 664099. The reversal of 664091 is 190466.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-664091 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 664091.

It is not a weakly prime, because it can be changed into another prime (664099) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332045 + 332046.

It is an arithmetic number, because the mean of its divisors is an integer number (332046).

2⁶⁶⁴⁰⁹¹ is an apocalyptic number.

664091 is a deficient number, since it is larger than the sum of its proper divisors (1).

664091 is an equidigital number, since it uses as much as digits as its factorization.

664091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1296, while the sum is 26.

The square root of 664091 is about 814.9177872645. The cubic root of 664091 is about 87.2453986731.

The spelling of 664091 in words is "six hundred sixty-four thousand, ninety-one".