207640681 has 2 divisors, whose sum is σ = 207640682. Its totient is φ = 207640680.

The previous prime is 207640637. The next prime is 207640717. The reversal of 207640681 is 186046702.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 202094656 + 5546025 = 14216^2 + 2355^2 .

It is a cyclic number.

It is not a de Polignac number, because 207640681 - 2¹⁷ = 207509609 is a prime.

It is a super-2 number, since 2×207640681² = 86229304812287522, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (207647681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 103820340 + 103820341.

It is an arithmetic number, because the mean of its divisors is an integer number (103820341).

Almost surely, 2^207640681 is an apocalyptic number.

It is an amenable number.

207640681 is a deficient number, since it is larger than the sum of its proper divisors (1).

207640681 is an equidigital number, since it uses as much as digits as its factorization.

207640681 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16128, while the sum is 34.

The square root of 207640681 is about 14409.7425723016. The cubic root of 207640681 is about 592.1578371828.

The spelling of 207640681 in words is "two hundred seven million, six hundred forty thousand, six hundred eighty-one".