19942591 has 2 divisors, whose sum is σ = 19942592. Its totient is φ = 19942590.

The previous prime is 19942567. The next prime is 19942597. The reversal of 19942591 is 19524991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19942591 - 2⁷ = 19942463 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (19942597) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9971295 + 9971296.

It is an arithmetic number, because the mean of its divisors is an integer number (9971296).

Almost surely, 2^19942591 is an apocalyptic number.

19942591 is a deficient number, since it is larger than the sum of its proper divisors (1).

19942591 is an equidigital number, since it uses as much as digits as its factorization.

19942591 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 29160, while the sum is 40.

The square root of 19942591 is about 4465.7128210399. The cubic root of 19942591 is about 271.1817927564.

The spelling of 19942591 in words is "nineteen million, nine hundred forty-two thousand, five hundred ninety-one".