191874421 has 2 divisors, whose sum is σ = 191874422. Its totient is φ = 191874420.

The previous prime is 191874409. The next prime is 191874437. The reversal of 191874421 is 124478191.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 115992900 + 75881521 = 10770^2 + 8711^2 .

It is an emirp because it is prime and its reverse (124478191) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 191874421 - 2¹³ = 191866229 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191874481) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95937210 + 95937211.

It is an arithmetic number, because the mean of its divisors is an integer number (95937211).

Almost surely, 2^191874421 is an apocalyptic number.

It is an amenable number.

191874421 is a deficient number, since it is larger than the sum of its proper divisors (1).

191874421 is an equidigital number, since it uses as much as digits as its factorization.

191874421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 16128, while the sum is 37.

The square root of 191874421 is about 13851.8742775121. The cubic root of 191874421 is about 576.7740255119.

The spelling of 191874421 in words is "one hundred ninety-one million, eight hundred seventy-four thousand, four hundred twenty-one".