990991081090 has 32 divisors (see below), whose sum is σ = 1787394457584. Its totient is φ = 395594357760.

The previous prime is 990991081081. The next prime is 990991081111. The reversal of 990991081090 is 90180199099.

It can be written as a sum of positive squares in 8 ways, for example, as 790674861601 + 200316219489 = 889199^2 + 447567^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 40113622 + ... + 40138318.

Almost surely, 2^990991081090 is an apocalyptic number.

990991081090 is a deficient number, since it is larger than the sum of its proper divisors (796403376494).

990991081090 is a wasteful number, since it uses less digits than its factorization.

990991081090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 32662.

The product of its (nonzero) digits is 472392, while the sum is 55.

The spelling of 990991081090 in words is "nine hundred ninety billion, nine hundred ninety-one million, eighty-one thousand, ninety".