19920191 has 4 divisors (see below), whose sum is σ = 19988472. Its totient is φ = 19851912.

The previous prime is 19920181. The next prime is 19920203. The reversal of 19920191 is 19102991.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19102991 = 1237 ⋅15443.

It is a cyclic number.

It is not a de Polignac number, because 19920191 - 2²² = 15725887 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19920181) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 33701 + ... + 34286.

It is an arithmetic number, because the mean of its divisors is an integer number (4997118).

Almost surely, 2^19920191 is an apocalyptic number.

19920191 is a deficient number, since it is larger than the sum of its proper divisors (68281).

19920191 is an equidigital number, since it uses as much as digits as its factorization.

19920191 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68280.

The product of its (nonzero) digits is 1458, while the sum is 32.

The square root of 19920191 is about 4463.2041181196. The cubic root of 19920191 is about 271.0802220710.

The spelling of 19920191 in words is "nineteen million, nine hundred twenty thousand, one hundred ninety-one".