190991904 has 24 divisors (see below), whose sum is σ = 501354000. Its totient is φ = 63663936.

The previous prime is 190991893. The next prime is 190991921. The reversal of 190991904 is 409199091.

It is a tau number, because it is divible by the number of its divisors (24).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 994654 + ... + 994845.

It is an arithmetic number, because the mean of its divisors is an integer number (20889750).

Almost surely, 2^190991904 is an apocalyptic number.

It is an amenable number.

190991904 is an abundant number, since it is smaller than the sum of its proper divisors (310362096).

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

190991904 is a wasteful number, since it uses less digits than its factorization.

190991904 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1989512 (or 1989504 counting only the distinct ones).

The product of its (nonzero) digits is 26244, while the sum is 42.

The square root of 190991904 is about 13819.9820549811. The cubic root of 190991904 is about 575.8883850089. Note that the first 3 decimals are identical.

The spelling of 190991904 in words is "one hundred ninety million, nine hundred ninety-one thousand, nine hundred four".