19688749136478 has 12 divisors (see below), whose sum is σ = 42658956462408. Its totient is φ = 6562916378820.

The previous prime is 19688749136467. The next prime is 19688749136509. The reversal of 19688749136478 is 87463194788691.

19688749136478 is a `hidden beast` number, since 1 + 9 + 6 + 8 + 8 + 7 + 4 + 9 + 136 + 478 = 666.

It is a junction number, because it is equal to n+sod(n) for n = 19688749136397 and 19688749136406.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 546909698218 + ... + 546909698253.

It is an arithmetic number, because the mean of its divisors is an integer number (3554913038534).

Almost surely, 2^{19688749136478} is an apocalyptic number.

19688749136478 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

19688749136478 is an abundant number, since it is smaller than the sum of its proper divisors (22970207325930).

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

19688749136478 is a wasteful number, since it uses less digits than its factorization.

19688749136478 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1093819396479 (or 1093819396476 counting only the distinct ones).

The product of its digits is 3511517184, while the sum is 81.

The spelling of 19688749136478 in words is "nineteen trillion, six hundred eighty-eight billion, seven hundred forty-nine million, one hundred thirty-six thousand, four hundred seventy-eight".