990139 has 4 divisors (see below), whose sum is σ = 999856. Its totient is φ = 980424.

The previous prime is 990137. The next prime is 990151. The reversal of 990139 is 931099.

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

It is a cyclic number.

It is not a de Polignac number, because 990139 - 2¹ = 990137 is a prime.

It is a Duffinian number.

990139 is a lucky number.

It is a self number, because there is not a number n which added to its sum of digits gives 990139.

It is not an unprimeable number, because it can be changed into a prime (990137) 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, 4704 + ... + 4909.

It is an arithmetic number, because the mean of its divisors is an integer number (249964).

2⁹⁹⁰¹³⁹ is an apocalyptic number.

990139 is a deficient number, since it is larger than the sum of its proper divisors (9717).

990139 is a wasteful number, since it uses less digits than its factorization.

990139 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9716.

The product of its (nonzero) digits is 2187, while the sum is 31.

The square root of 990139 is about 995.0572847831. The cubic root of 990139 is about 99.6702136049.

The spelling of 990139 in words is "nine hundred ninety thousand, one hundred thirty-nine".