990431904 has 144 divisors (see below), whose sum is σ = 3299468256. Its totient is φ = 257241600.

The previous prime is 990431899. The next prime is 990431909. The reversal of 990431904 is 409134099.

It is an interprime number because it is at equal distance from previous prime (990431899) and next prime (990431909).

It is a super-2 number, since 2×990431904² = 1961910712922130432, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (990431909) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 42174 + ... + 61314.

It is an arithmetic number, because the mean of its divisors is an integer number (22912974).

Almost surely, 2^990431904 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 990431904, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1649734128).

990431904 is an abundant number, since it is smaller than the sum of its proper divisors (2309036352).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

990431904 is a wasteful number, since it uses less digits than its factorization.

990431904 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19179 (or 19164 counting only the distinct ones).

The product of its (nonzero) digits is 34992, while the sum is 39.

The square root of 990431904 is about 31471.1281018015. The cubic root of 990431904 is about 996.8004081975.

The spelling of 990431904 in words is "nine hundred ninety million, four hundred thirty-one thousand, nine hundred four".