990991011 has 4 divisors (see below), whose sum is σ = 1321321352. Its totient is φ = 660660672.

The previous prime is 990991009. The next prime is 990991019. The reversal of 990991011 is 110199099.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 110199099 = 3 ⋅36733033.

It is not a de Polignac number, because 990991011 - 2¹ = 990991009 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (990991019) 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, 165165166 + ... + 165165171.

It is an arithmetic number, because the mean of its divisors is an integer number (330330338).

Almost surely, 2^990991011 is an apocalyptic number.

990991011 is a deficient number, since it is larger than the sum of its proper divisors (330330341).

990991011 is a wasteful number, since it uses less digits than its factorization.

990991011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 330330340.

The product of its (nonzero) digits is 6561, while the sum is 39.

The square root of 990991011 is about 31480.0097045728. The cubic root of 990991011 is about 996.9879402718.

The spelling of 990991011 in words is "nine hundred ninety million, nine hundred ninety-one thousand, eleven".