191421493 has 2 divisors, whose sum is σ = 191421494. Its totient is φ = 191421492.

The previous prime is 191421463. The next prime is 191421499. The reversal of 191421493 is 394124191.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 178302609 + 13118884 = 13353^2 + 3622^2 .

It is an emirp because it is prime and its reverse (394124191) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 191421493 - 2⁹ = 191420981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (191421499) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 95710746 + 95710747.

It is an arithmetic number, because the mean of its divisors is an integer number (95710747).

Almost surely, 2^191421493 is an apocalyptic number.

It is an amenable number.

191421493 is a deficient number, since it is larger than the sum of its proper divisors (1).

191421493 is an equidigital number, since it uses as much as digits as its factorization.

191421493 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 7776, while the sum is 34.

The square root of 191421493 is about 13835.5156391079. The cubic root of 191421493 is about 576.3198344697.

The spelling of 191421493 in words is "one hundred ninety-one million, four hundred twenty-one thousand, four hundred ninety-three".