664619 has 2 divisors, whose sum is σ = 664620. Its totient is φ = 664618.

The previous prime is 664613. The next prime is 664621. The reversal of 664619 is 916466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 664619 - 2⁴ = 664603 is a prime.

It is a super-2 number, since 2×664619² = 883436830322, which contains 22 as substring.

Together with 664621, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (664613) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332309 + 332310.

It is an arithmetic number, because the mean of its divisors is an integer number (332310).

2⁶⁶⁴⁶¹⁹ is an apocalyptic number.

664619 is a deficient number, since it is larger than the sum of its proper divisors (1).

664619 is an equidigital number, since it uses as much as digits as its factorization.

664619 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 32.

The square root of 664619 is about 815.2416819570. The cubic root of 664619 is about 87.2685146654.

The spelling of 664619 in words is "six hundred sixty-four thousand, six hundred nineteen".