647640481 has 2 divisors, whose sum is σ = 647640482. Its totient is φ = 647640480.

The previous prime is 647640431. The next prime is 647640533. The reversal of 647640481 is 184046746.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 631768225 + 15872256 = 25135^2 + 3984^2 .

It is a cyclic number.

It is not a de Polignac number, because 647640481 - 2⁷ = 647640353 is a prime.

It is a super-2 number, since 2×647640481² = 838876385259822722, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (647640431) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 323820240 + 323820241.

It is an arithmetic number, because the mean of its divisors is an integer number (323820241).

Almost surely, 2^647640481 is an apocalyptic number.

It is an amenable number.

647640481 is a deficient number, since it is larger than the sum of its proper divisors (1).

647640481 is an equidigital number, since it uses as much as digits as its factorization.

647640481 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 129024, while the sum is 40.

The square root of 647640481 is about 25448.7815228942. The cubic root of 647640481 is about 865.1896767381.

The spelling of 647640481 in words is "six hundred forty-seven million, six hundred forty thousand, four hundred eighty-one".