19778694813738 has 24 divisors (see below), whose sum is σ = 48975815729568. Its totient is φ = 5651055661032.

The previous prime is 19778694813721. The next prime is 19778694813763. The reversal of 19778694813738 is 83731849687791.

19778694813738 is a `hidden beast` number, since 1 + 9 + 7 + 7 + 8 + 69 + 481 + 3 + 73 + 8 = 666.

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 11 ways as a sum of consecutive naturals, for example, 78486884056 + ... + 78486884307.

It is an arithmetic number, because the mean of its divisors is an integer number (2040658988732).

Almost surely, 2^{19778694813738} is an apocalyptic number.

19778694813738 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

19778694813738 is an abundant number, since it is smaller than the sum of its proper divisors (29197120915830).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

19778694813738 is a wasteful number, since it uses less digits than its factorization.

19778694813738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 156973768378 (or 156973768375 counting only the distinct ones).

The product of its digits is 3072577536, while the sum is 81.

The spelling of 19778694813738 in words is "nineteen trillion, seven hundred seventy-eight billion, six hundred ninety-four million, eight hundred thirteen thousand, seven hundred thirty-eight".