191985521 has 12 divisors (see below), whose sum is σ = 237589632. Its totient is φ = 151899696.

The previous prime is 191985517. The next prime is 191985523. The reversal of 191985521 is 125589191.

It is not a de Polignac number, because 191985521 - 2² = 191985517 is a prime.

It is a Smith number, since the sum of its digits (41) coincides with the sum of the digits of its prime factors.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (191985523) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 79961 + ... + 82326.

It is an arithmetic number, because the mean of its divisors is an integer number (19799136).

Almost surely, 2^191985521 is an apocalyptic number.

It is an amenable number.

191985521 is a deficient number, since it is larger than the sum of its proper divisors (45604111).

191985521 is a wasteful number, since it uses less digits than its factorization.

191985521 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 162320 (or 162307 counting only the distinct ones).

The product of its digits is 32400, while the sum is 41.

The square root of 191985521 is about 13855.8839847914. The cubic root of 191985521 is about 576.8853261393.

The spelling of 191985521 in words is "one hundred ninety-one million, nine hundred eighty-five thousand, five hundred twenty-one".