647670691 has 2 divisors, whose sum is σ = 647670692. Its totient is φ = 647670690.

The previous prime is 647670637. The next prime is 647670701. The reversal of 647670691 is 196076746.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 647670691 - 2¹¹ = 647668643 is a prime.

It is not a weakly prime, because it can be changed into another prime (647670091) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323835345 + 323835346.

It is an arithmetic number, because the mean of its divisors is an integer number (323835346).

Almost surely, 2^647670691 is an apocalyptic number.

647670691 is a deficient number, since it is larger than the sum of its proper divisors (1).

647670691 is an equidigital number, since it uses as much as digits as its factorization.

647670691 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 381024, while the sum is 46.

The square root of 647670691 is about 25449.3750610894. The cubic root of 647670691 is about 865.2031291471.

The spelling of 647670691 in words is "six hundred forty-seven million, six hundred seventy thousand, six hundred ninety-one".