191939481221 has 4 divisors (see below), whose sum is σ = 202041559200. Its totient is φ = 181837403244.

The previous prime is 191939481179. The next prime is 191939481233. The reversal of 191939481221 is 122184939191.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 122184939191 = 7 ⋅17454991313.

It is a cyclic number.

It is not a de Polignac number, because 191939481221 - 2⁶ = 191939481157 is a prime.

It is a super-2 number, since 2×191939481221² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 191939481221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (191939481421) 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 3 ways as a sum of consecutive naturals, for example, 5051038961 + ... + 5051038998.

It is an arithmetic number, because the mean of its divisors is an integer number (50510389800).

Almost surely, 2^191939481221 is an apocalyptic number.

It is an amenable number.

191939481221 is a deficient number, since it is larger than the sum of its proper divisors (10102077979).

191939481221 is a wasteful number, since it uses less digits than its factorization.

191939481221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10102077978.

The product of its digits is 279936, while the sum is 50.

The spelling of 191939481221 in words is "one hundred ninety-one billion, nine hundred thirty-nine million, four hundred eighty-one thousand, two hundred twenty-one".