19873891 has 2 divisors, whose sum is σ = 19873892. Its totient is φ = 19873890.

The previous prime is 19873877. The next prime is 19873913. The reversal of 19873891 is 19837891.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 19873891 - 2⁹ = 19873379 is a prime.

It is not a weakly prime, because it can be changed into another prime (19873801) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9936945 + 9936946.

It is an arithmetic number, because the mean of its divisors is an integer number (9936946).

Almost surely, 2^19873891 is an apocalyptic number.

19873891 is a deficient number, since it is larger than the sum of its proper divisors (1).

19873891 is an equidigital number, since it uses as much as digits as its factorization.

19873891 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108864, while the sum is 46.

The square root of 19873891 is about 4458.0142440329. The cubic root of 19873891 is about 270.8700374923.

The spelling of 19873891 in words is "nineteen million, eight hundred seventy-three thousand, eight hundred ninety-one".