199101990 has 64 divisors (see below), whose sum is σ = 489265920. Its totient is φ = 51838080.

The previous prime is 199101979. The next prime is 199102003. The reversal of 199101990 is 99101991.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 348405 + ... + 348975.

It is an arithmetic number, because the mean of its divisors is an integer number (7644780).

Almost surely, 2^199101990 is an apocalyptic number.

199101990 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is a practical number, because each smaller number is the sum of distinct divisors of 199101990, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (244632960).

199101990 is an abundant number, since it is smaller than the sum of its proper divisors (290163930).

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

199101990 is a wasteful number, since it uses less digits than its factorization.

199101990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 837.

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

The square root of 199101990 is about 14110.3504563140. The cubic root of 199101990 is about 583.9269686464.

Subtracting from 199101990 its reverse (99101991), we obtain a palindrome (99999999).

The spelling of 199101990 in words is "one hundred ninety-nine million, one hundred one thousand, nine hundred ninety".