990578 has 4 divisors (see below), whose sum is σ = 1485870. Its totient is φ = 495288.

The previous prime is 990559. The next prime is 990589. The reversal of 990578 is 875099.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 875099 = 31 ⋅28229.

It can be written as a sum of positive squares in only one way, i.e., 908209 + 82369 = 953^2 + 287^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 247643 + ... + 247646.

2⁹⁹⁰⁵⁷⁸ is an apocalyptic number.

990578 is a deficient number, since it is larger than the sum of its proper divisors (495292).

990578 is a wasteful number, since it uses less digits than its factorization.

990578 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 495291.

The product of its (nonzero) digits is 22680, while the sum is 38.

The square root of 990578 is about 995.2778506528. The cubic root of 990578 is about 99.6849417588.

The spelling of 990578 in words is "nine hundred ninety thousand, five hundred seventy-eight".