19911868 has 12 divisors (see below), whose sum is σ = 34973512. Its totient is φ = 9919440.

The previous prime is 19911821. The next prime is 19911877. The reversal of 19911868 is 86811991.

It is a happy number.

It is a hoax number, since the sum of its digits (43) coincides with the sum of the digits of its distinct prime factors.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 7878 + ... + 10093.

Almost surely, 2^19911868 is an apocalyptic number.

It is an amenable number.

19911868 is a deficient number, since it is larger than the sum of its proper divisors (15061644).

19911868 is a wasteful number, since it uses less digits than its factorization.

19911868 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18252 (or 18250 counting only the distinct ones).

The product of its digits is 31104, while the sum is 43.

The square root of 19911868 is about 4462.2716188058. The cubic root of 19911868 is about 271.0424628115.

The spelling of 19911868 in words is "nineteen million, nine hundred eleven thousand, eight hundred sixty-eight".