191020040 has 32 divisors (see below), whose sum is σ = 430479360. Its totient is φ = 76286400.

The previous prime is 191020009. The next prime is 191020073. The reversal of 191020040 is 40020191.

It is a happy number.

It is a Cunningham number, because it is equal to 13821²-1.

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, 24185 + ... + 31095.

It is an arithmetic number, because the mean of its divisors is an integer number (13452480).

Almost surely, 2^191020040 is an apocalyptic number.

191020040 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

191020040 is an abundant number, since it is smaller than the sum of its proper divisors (239459320).

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

191020040 is a wasteful number, since it uses less digits than its factorization.

191020040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7613 (or 7609 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 191020040 is about 13820.9999638232. Note that the first 4 decimals coincide. The cubic root of 191020040 is about 575.9166626473.

The spelling of 191020040 in words is "one hundred ninety-one million, twenty thousand, forty".