647965993 has 2 divisors, whose sum is σ = 647965994. Its totient is φ = 647965992.

The previous prime is 647965957. The next prime is 647966003. The reversal of 647965993 is 399569746.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 632623104 + 15342889 = 25152^2 + 3917^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-647965993 is a prime.

It is not a weakly prime, because it can be changed into another prime (647965933) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323982996 + 323982997.

It is an arithmetic number, because the mean of its divisors is an integer number (323982997).

Almost surely, 2^647965993 is an apocalyptic number.

It is an amenable number.

647965993 is a deficient number, since it is larger than the sum of its proper divisors (1).

647965993 is an equidigital number, since it uses as much as digits as its factorization.

647965993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11022480, while the sum is 58.

The square root of 647965993 is about 25455.1761533877. The cubic root of 647965993 is about 865.3346040859.

The spelling of 647965993 in words is "six hundred forty-seven million, nine hundred sixty-five thousand, nine hundred ninety-three".