19981867 has 2 divisors, whose sum is σ = 19981868. Its totient is φ = 19981866.

The previous prime is 19981807. The next prime is 19981873. The reversal of 19981867 is 76818991.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 19981867 - 2²³ = 11593259 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 19981867.

It is not a weakly prime, because it can be changed into another prime (19981807) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9990933 + 9990934.

It is an arithmetic number, because the mean of its divisors is an integer number (9990934).

Almost surely, 2^19981867 is an apocalyptic number.

19981867 is a deficient number, since it is larger than the sum of its proper divisors (1).

19981867 is an equidigital number, since it uses as much as digits as its factorization.

19981867 is an evil number, because the sum of its binary digits is even.

The product of its digits is 217728, while the sum is 49.

The square root of 19981867 is about 4470.1081642394. The cubic root of 19981867 is about 271.3597026305.

The spelling of 19981867 in words is "nineteen million, nine hundred eighty-one thousand, eight hundred sixty-seven".