191001920 has 56 divisors (see below), whose sum is σ = 456057000. Its totient is φ = 76193792.

The previous prime is 191001907. The next prime is 191001931. The reversal of 191001920 is 29100191.

It can be written as a sum of positive squares in 4 ways, for example, as 25725184 + 165276736 = 5072^2 + 12856^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 181556 + ... + 182604.

It is an arithmetic number, because the mean of its divisors is an integer number (8143875).

Almost surely, 2^191001920 is an apocalyptic number.

191001920 is a gapful number since it is divisible by the number (10) 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 191001920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (228028500).

191001920 is an abundant number, since it is smaller than the sum of its proper divisors (265055080).

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

191001920 is a wasteful number, since it uses less digits than its factorization.

191001920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1635 (or 1625 counting only the distinct ones).

The product of its (nonzero) digits is 162, while the sum is 23.

The square root of 191001920 is about 13820.3444240728. The cubic root of 191001920 is about 575.8984517484.

The spelling of 191001920 in words is "one hundred ninety-one million, one thousand, nine hundred twenty".