647665693 has 2 divisors, whose sum is σ = 647665694. Its totient is φ = 647665692.

The previous prime is 647665633. The next prime is 647665721. The reversal of 647665693 is 396566746.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 609250489 + 38415204 = 24683^2 + 6198^2 .

It is a cyclic number.

It is not a de Polignac number, because 647665693 - 2¹⁷ = 647534621 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 647665693.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (647665633) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323832846 + 323832847.

It is an arithmetic number, because the mean of its divisors is an integer number (323832847).

Almost surely, 2^647665693 is an apocalyptic number.

It is an amenable number.

647665693 is a deficient number, since it is larger than the sum of its proper divisors (1).

647665693 is an equidigital number, since it uses as much as digits as its factorization.

647665693 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4898880, while the sum is 52.

The square root of 647665693 is about 25449.2768659544. The cubic root of 647665693 is about 865.2009035837.

The spelling of 647665693 in words is "six hundred forty-seven million, six hundred sixty-five thousand, six hundred ninety-three".