647660879 has 2 divisors, whose sum is σ = 647660880. Its totient is φ = 647660878.

The previous prime is 647660861. The next prime is 647660939. The reversal of 647660879 is 978066746.

It is a happy number.

647660879 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-647660879 is a prime.

It is a super-2 number, since 2×647660879² = 838929228374105282, which contains 22 as substring.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 647660879.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (647660179) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323830439 + 323830440.

It is an arithmetic number, because the mean of its divisors is an integer number (323830440).

Almost surely, 2^647660879 is an apocalyptic number.

647660879 is a deficient number, since it is larger than the sum of its proper divisors (1).

647660879 is an equidigital number, since it uses as much as digits as its factorization.

647660879 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3048192, while the sum is 53.

The square root of 647660879 is about 25449.1822854881. The cubic root of 647660879 is about 865.1987599431.

The spelling of 647660879 in words is "six hundred forty-seven million, six hundred sixty thousand, eight hundred seventy-nine".