990881918 has 32 divisors (see below), whose sum is σ = 1691141760. Its totient is φ = 432149760.

The previous prime is 990881917. The next prime is 990881921. The reversal of 990881918 is 819188099.

It is a Smith number, since the sum of its digits (53) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a self number, because there is not a number n which added to its sum of digits gives 990881918.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (990881917) 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, 21458 + ... + 49418.

It is an arithmetic number, because the mean of its divisors is an integer number (52848180).

Almost surely, 2^990881918 is an apocalyptic number.

990881918 is a deficient number, since it is larger than the sum of its proper divisors (700259842).

990881918 is a wasteful number, since it uses less digits than its factorization.

990881918 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 28052.

The product of its (nonzero) digits is 373248, while the sum is 53.

The square root of 990881918 is about 31478.2769223476. The cubic root of 990881918 is about 996.9513545391.

The spelling of 990881918 in words is "nine hundred ninety million, eight hundred eighty-one thousand, nine hundred eighteen".