990649 has 4 divisors (see below), whose sum is σ = 1080720. Its totient is φ = 900580.

The previous prime is 990643. The next prime is 990673. The reversal of 990649 is 946099.

990649 = 157² + 158² + ... + 189².

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 990649 - 2⁹ = 990137 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (990643) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 45019 + ... + 45040.

It is an arithmetic number, because the mean of its divisors is an integer number (270180).

2⁹⁹⁰⁶⁴⁹ is an apocalyptic number.

It is an amenable number.

990649 is a deficient number, since it is larger than the sum of its proper divisors (90071).

990649 is a wasteful number, since it uses less digits than its factorization.

990649 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 90070.

The product of its (nonzero) digits is 17496, while the sum is 37.

The square root of 990649 is about 995.3135184453. The cubic root of 990649 is about 99.6873233521.

The spelling of 990649 in words is "nine hundred ninety thousand, six hundred forty-nine".