19920391 has 2 divisors, whose sum is σ = 19920392. Its totient is φ = 19920390.

The previous prime is 19920353. The next prime is 19920401. The reversal of 19920391 is 19302991.

It is a strong prime.

It is an emirp because it is prime and its reverse (19302991) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 19920391 - 2¹¹ = 19918343 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19920491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9960195 + 9960196.

It is an arithmetic number, because the mean of its divisors is an integer number (9960196).

Almost surely, 2^19920391 is an apocalyptic number.

19920391 is a deficient number, since it is larger than the sum of its proper divisors (1).

19920391 is an equidigital number, since it uses as much as digits as its factorization.

19920391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4374, while the sum is 34.

The square root of 19920391 is about 4463.2265234917. The cubic root of 19920391 is about 271.0811292890.

The spelling of 19920391 in words is "nineteen million, nine hundred twenty thousand, three hundred ninety-one".