19806704638 has 12 divisors (see below), whose sum is σ = 34560678672. Its totient is φ = 8488587660.

The previous prime is 19806704597. The next prime is 19806704647. The reversal of 19806704638 is 83640760891.

It is a happy number.

It is a super-2 number, since 2×19806704638² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 101054518 + ... + 101054713.

It is an arithmetic number, because the mean of its divisors is an integer number (2880056556).

Almost surely, 2^19806704638 is an apocalyptic number.

19806704638 is a deficient number, since it is larger than the sum of its proper divisors (14753974034).

19806704638 is a wasteful number, since it uses less digits than its factorization.

19806704638 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 202109247 (or 202109240 counting only the distinct ones).

The product of its (nonzero) digits is 1741824, while the sum is 52.

The spelling of 19806704638 in words is "nineteen billion, eight hundred six million, seven hundred four thousand, six hundred thirty-eight".