7987681 has 4 divisors (see below), whose sum is σ = 8602132. Its totient is φ = 7373232.

The previous prime is 7987669. The next prime is 7987687. The reversal of 7987681 is 1867897.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1018081 + 6969600 = 1009^2 + 2640^2 .

It is a cyclic number.

It is not a de Polignac number, because 7987681 - 2⁵ = 7987649 is a prime.

It is a super-2 number, since 2×7987681² = 127606095515522, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (7987687) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 307206 + ... + 307231.

It is an arithmetic number, because the mean of its divisors is an integer number (2150533).

Almost surely, 2^7987681 is an apocalyptic number.

It is an amenable number.

7987681 is a deficient number, since it is larger than the sum of its proper divisors (614451).

7987681 is a wasteful number, since it uses less digits than its factorization.

7987681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 614450.

The product of its digits is 169344, while the sum is 46.

The square root of 7987681 is about 2826.2485736396. The cubic root of 7987681 is about 199.8972889279.

It can be divided in two parts, 7987 and 681, that added together give a palindrome (8668).

The spelling of 7987681 in words is "seven million, nine hundred eighty-seven thousand, six hundred eighty-one".