191621143 has 4 divisors (see below), whose sum is σ = 218995600. Its totient is φ = 164246688.

The previous prime is 191621141. The next prime is 191621149. The reversal of 191621143 is 341126191.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 191621143 - 2¹ = 191621141 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 (191621141) 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, 13687218 + ... + 13687231.

It is an arithmetic number, because the mean of its divisors is an integer number (54748900).

Almost surely, 2^191621143 is an apocalyptic number.

191621143 is a deficient number, since it is larger than the sum of its proper divisors (27374457).

191621143 is an equidigital number, since it uses as much as digits as its factorization.

191621143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 27374456.

The product of its digits is 1296, while the sum is 28.

The square root of 191621143 is about 13842.7288855919. The cubic root of 191621143 is about 576.5201294201.

The spelling of 191621143 in words is "one hundred ninety-one million, six hundred twenty-one thousand, one hundred forty-three".