189191808 has 128 divisors (see below), whose sum is σ = 601473600. Its totient is φ = 58199040.

The previous prime is 189191801. The next prime is 189191809. The reversal of 189191808 is 808191981.

It is a tau number, because it is divible by the number of its divisors (128).

It is not an unprimeable number, because it can be changed into a prime (189191801) 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, 42823 + ... + 47033.

Almost surely, 2^189191808 is an apocalyptic number.

189191808 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 189191808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (300736800).

189191808 is an abundant number, since it is smaller than the sum of its proper divisors (412281792).

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

189191808 is a wasteful number, since it uses less digits than its factorization.

189191808 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4247 (or 4229 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 45.

The square root of 189191808 is about 13754.7013053719. The cubic root of 189191808 is about 574.0734243830.

The spelling of 189191808 in words is "one hundred eighty-nine million, one hundred ninety-one thousand, eight hundred eight".