19816939 has 6 divisors (see below), whose sum is σ = 20249804. Its totient is φ = 19393140.

The previous prime is 19816933. The next prime is 19816987. The reversal of 19816939 is 93961891.

It is not a de Polignac number, because 19816939 - 2³ = 19816931 is a prime.

It is a super-2 number, since 2×19816939² = 785422142659442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (19816931) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 2277 + ... + 6694.

Almost surely, 2^19816939 is an apocalyptic number.

19816939 is a deficient number, since it is larger than the sum of its proper divisors (432865).

19816939 is an frugal number, since it uses more digits than its factorization.

19816939 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9065 (or 9018 counting only the distinct ones).

The product of its digits is 104976, while the sum is 46.

The square root of 19816939 is about 4451.6220639223. The cubic root of 19816939 is about 270.6110486223.

The spelling of 19816939 in words is "nineteen million, eight hundred sixteen thousand, nine hundred thirty-nine".