647661319 has 2 divisors, whose sum is σ = 647661320. Its totient is φ = 647661318.

The previous prime is 647661317. The next prime is 647661373. The reversal of 647661319 is 913166746.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 647661319 - 2¹ = 647661317 is a prime.

It is a super-2 number, since 2×647661319² = 838930368257639522, which contains 22 as substring.

Together with 647661317, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (647661317) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323830659 + 323830660.

It is an arithmetic number, because the mean of its divisors is an integer number (323830660).

Almost surely, 2^647661319 is an apocalyptic number.

647661319 is a deficient number, since it is larger than the sum of its proper divisors (1).

647661319 is an equidigital number, since it uses as much as digits as its factorization.

647661319 is an evil number, because the sum of its binary digits is even.

The product of its digits is 163296, while the sum is 43.

The square root of 647661319 is about 25449.1909301651. The cubic root of 647661319 is about 865.1989558725.

The spelling of 647661319 in words is "six hundred forty-seven million, six hundred sixty-one thousand, three hundred nineteen".