990655921 has 16 divisors (see below), whose sum is σ = 1046629440. Its totient is φ = 936290880.

The previous prime is 990655907. The next prime is 990655949. The reversal of 990655921 is 129556099.

990655921 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 990655921 - 2²³ = 982267313 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (990655951) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 400330 + ... + 402796.

It is an arithmetic number, because the mean of its divisors is an integer number (65414340).

Almost surely, 2^990655921 is an apocalyptic number.

It is an amenable number.

990655921 is a deficient number, since it is larger than the sum of its proper divisors (55973519).

990655921 is a wasteful number, since it uses less digits than its factorization.

990655921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2784.

The product of its (nonzero) digits is 218700, while the sum is 46.

The square root of 990655921 is about 31474.6869881179. The cubic root of 990655921 is about 996.8755550106.

The spelling of 990655921 in words is "nine hundred ninety million, six hundred fifty-five thousand, nine hundred twenty-one".