990921790 has 16 divisors (see below), whose sum is σ = 1831866912. Its totient is φ = 385655904.

The previous prime is 990921787. The next prime is 990921791. The reversal of 990921790 is 97129099.

It is a self number, because there is not a number n which added to its sum of digits gives 990921790.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (990921791) 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 7 ways as a sum of consecutive naturals, for example, 1338714 + ... + 1339453.

It is an arithmetic number, because the mean of its divisors is an integer number (114491682).

Almost surely, 2^990921790 is an apocalyptic number.

990921790 is a deficient number, since it is larger than the sum of its proper divisors (840945122).

990921790 is a wasteful number, since it uses less digits than its factorization.

990921790 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2678211.

The product of its (nonzero) digits is 91854, while the sum is 46.

The square root of 990921790 is about 31478.9102416205. The cubic root of 990921790 is about 996.9647264356.

The spelling of 990921790 in words is "nine hundred ninety million, nine hundred twenty-one thousand, seven hundred ninety".