9990661 has 2 divisors, whose sum is σ = 9990662. Its totient is φ = 9990660.

The previous prime is 9990653. The next prime is 9990667. The reversal of 9990661 is 1660999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 7873636 + 2117025 = 2806^2 + 1455^2 .

It is a cyclic number.

It is not a de Polignac number, because 9990661 - 2³ = 9990653 is a prime.

It is a super-3 number, since 3×9990661³ (a number of 22 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9990667) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4995330 + 4995331.

It is an arithmetic number, because the mean of its divisors is an integer number (4995331).

Almost surely, 2^9990661 is an apocalyptic number.

It is an amenable number.

9990661 is a deficient number, since it is larger than the sum of its proper divisors (1).

9990661 is an equidigital number, since it uses as much as digits as its factorization.

9990661 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 26244, while the sum is 40.

The square root of 9990661 is about 3160.8006896987. The cubic root of 9990661 is about 215.3763805623.

The spelling of 9990661 in words is "nine million, nine hundred ninety thousand, six hundred sixty-one".