7717681 has 2 divisors, whose sum is σ = 7717682. Its totient is φ = 7717680.

The previous prime is 7717679. The next prime is 7717709. The reversal of 7717681 is 1867177.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6843456 + 874225 = 2616^2 + 935^2 .

It is a cyclic number.

It is not a de Polignac number, because 7717681 - 2¹ = 7717679 is a prime.

It is a super-2 number, since 2×7717681² = 119125200035522, which contains 22 as substring.

Together with 7717679, it forms a pair of twin primes.

7717681 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 7717681.

It is not a weakly prime, because it can be changed into another prime (7717631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3858840 + 3858841.

It is an arithmetic number, because the mean of its divisors is an integer number (3858841).

Almost surely, 2^7717681 is an apocalyptic number.

It is an amenable number.

7717681 is a deficient number, since it is larger than the sum of its proper divisors (1).

7717681 is an equidigital number, since it uses as much as digits as its factorization.

7717681 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16464, while the sum is 37.

The square root of 7717681 is about 2778.0714533647. The cubic root of 7717681 is about 197.6191109738.

The spelling of 7717681 in words is "seven million, seven hundred seventeen thousand, six hundred eighty-one".