7666681 has 6 divisors (see below), whose sum is σ = 8427146. Its totient is φ = 6969600.

The previous prime is 7666669. The next prime is 7666693. The reversal of 7666681 is 1866667.

It is an interprime number because it is at equal distance from previous prime (7666669) and next prime (7666693).

It can be written as a sum of positive squares in only one way, i.e., 6456681 + 1210000 = 2541^2 + 1100^2 .

It is not a de Polignac number, because 7666681 - 2⁷ = 7666553 is a prime.

It is a super-2 number, since 2×7666681² = 117555995111522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7666621) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 31560 + ... + 31801.

Almost surely, 2^7666681 is an apocalyptic number.

It is an amenable number.

7666681 is a deficient number, since it is larger than the sum of its proper divisors (760465).

7666681 is a wasteful number, since it uses less digits than its factorization.

7666681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 63383 (or 63372 counting only the distinct ones).

The product of its digits is 72576, while the sum is 40.

The square root of 7666681 is about 2768.8772092673. The cubic root of 7666681 is about 197.1828462053.

It can be divided in two parts, 766 and 6681, that added together give a palindrome (7447).

The spelling of 7666681 in words is "seven million, six hundred sixty-six thousand, six hundred eighty-one".