990651 has 4 divisors (see below), whose sum is σ = 1320872. Its totient is φ = 660432.

The previous prime is 990643. The next prime is 990673. The reversal of 990651 is 156099.

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

It is not a de Polignac number, because 990651 - 2³ = 990643 is a prime.

It is an Ulam number.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (990631) 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, 165106 + ... + 165111.

It is an arithmetic number, because the mean of its divisors is an integer number (330218).

2⁹⁹⁰⁶⁵¹ is an apocalyptic number.

990651 is a deficient number, since it is larger than the sum of its proper divisors (330221).

990651 is a wasteful number, since it uses less digits than its factorization.

990651 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330220.

The product of its (nonzero) digits is 2430, while the sum is 30.

The square root of 990651 is about 995.3145231534. The cubic root of 990651 is about 99.6873904376.

The spelling of 990651 in words is "nine hundred ninety thousand, six hundred fifty-one".