647640319 has 2 divisors, whose sum is σ = 647640320. Its totient is φ = 647640318.

The previous prime is 647640299. The next prime is 647640349. The reversal of 647640319 is 913046746.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 647640319 - 2¹⁵ = 647607551 is a prime.

It is a super-2 number, since 2×647640319² = 838875965588843522, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (647640349) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323820159 + 323820160.

It is an arithmetic number, because the mean of its divisors is an integer number (323820160).

Almost surely, 2^647640319 is an apocalyptic number.

647640319 is a deficient number, since it is larger than the sum of its proper divisors (1).

647640319 is an equidigital number, since it uses as much as digits as its factorization.

647640319 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 108864, while the sum is 40.

The square root of 647640319 is about 25448.7783400304. The cubic root of 647640319 is about 865.1896045990.

The spelling of 647640319 in words is "six hundred forty-seven million, six hundred forty thousand, three hundred nineteen".