990866 has 4 divisors (see below), whose sum is σ = 1486302. Its totient is φ = 495432.

The previous prime is 990851. The next prime is 990881. The reversal of 990866 is 668099.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 668099 = 359 ⋅1861.

It is an interprime number because it is at equal distance from previous prime (990851) and next prime (990881).

It can be written as a sum of positive squares in only one way, i.e., 990025 + 841 = 995^2 + 29^2 .

It is an Ulam number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 247715 + ... + 247718.

2⁹⁹⁰⁸⁶⁶ is an apocalyptic number.

990866 is a deficient number, since it is larger than the sum of its proper divisors (495436).

990866 is a wasteful number, since it uses less digits than its factorization.

990866 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 495435.

The product of its (nonzero) digits is 23328, while the sum is 38.

The square root of 990866 is about 995.4225233538. The cubic root of 990866 is about 99.6946016010.

The spelling of 990866 in words is "nine hundred ninety thousand, eight hundred sixty-six".