191929421 has 2 divisors, whose sum is σ = 191929422. Its totient is φ = 191929420.

The previous prime is 191929379. The next prime is 191929447. The reversal of 191929421 is 124929191.

191929421 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 120340900 + 71588521 = 10970^2 + 8461^2 .

It is an emirp because it is prime and its reverse (124929191) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 191929421 - 2²² = 187735117 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191929021) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95964710 + 95964711.

It is an arithmetic number, because the mean of its divisors is an integer number (95964711).

Almost surely, 2^191929421 is an apocalyptic number.

It is an amenable number.

191929421 is a deficient number, since it is larger than the sum of its proper divisors (1).

191929421 is an equidigital number, since it uses as much as digits as its factorization.

191929421 is an evil number, because the sum of its binary digits is even.

The product of its digits is 11664, while the sum is 38.

The square root of 191929421 is about 13853.8594261671. The cubic root of 191929421 is about 576.8291302008.

The spelling of 191929421 in words is "one hundred ninety-one million, nine hundred twenty-nine thousand, four hundred twenty-one".