9990681 has 4 divisors (see below), whose sum is σ = 13320912. Its totient is φ = 6660452.

The previous prime is 9990677. The next prime is 9990683. The reversal of 9990681 is 1860999.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 9990681 - 2² = 9990677 is a prime.

It is a super-2 number, since 2×9990681² = 199627413687522, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (9990683) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1665111 + ... + 1665116.

It is an arithmetic number, because the mean of its divisors is an integer number (3330228).

Almost surely, 2^9990681 is an apocalyptic number.

It is an amenable number.

9990681 is a deficient number, since it is larger than the sum of its proper divisors (3330231).

9990681 is a wasteful number, since it uses less digits than its factorization.

9990681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3330230.

The product of its (nonzero) digits is 34992, while the sum is 42.

The square root of 9990681 is about 3160.8038534525. The cubic root of 9990681 is about 215.3765242807.

The spelling of 9990681 in words is "nine million, nine hundred ninety thousand, six hundred eighty-one".