664405739 has 2 divisors, whose sum is σ = 664405740. Its totient is φ = 664405738.

The previous prime is 664405727. The next prime is 664405741. The reversal of 664405739 is 937504466.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 664405739 - 2²⁴ = 647628523 is a prime.

It is a super-2 number, since 2×664405739² = 882869972032272242, which contains 22 as substring.

Together with 664405741, it forms a pair of twin primes.

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 664405739.

It is not a weakly prime, because it can be changed into another prime (664455739) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332202869 + 332202870.

It is an arithmetic number, because the mean of its divisors is an integer number (332202870).

Almost surely, 2^664405739 is an apocalyptic number.

664405739 is a deficient number, since it is larger than the sum of its proper divisors (1).

664405739 is an equidigital number, since it uses as much as digits as its factorization.

664405739 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 544320, while the sum is 44.

The square root of 664405739 is about 25776.0691145877. The cubic root of 664405739 is about 872.5917951164.

The spelling of 664405739 in words is "six hundred sixty-four million, four hundred five thousand, seven hundred thirty-nine".