19681651836 has 216 divisors, whose sum is σ = 65474712576. Its totient is φ = 5111981280.

The previous prime is 19681651831. The next prime is 19681651853. The reversal of 19681651836 is 63815618691.

19681651836 is a `hidden beast` number, since 1 + 96 + 8 + 1 + 6 + 518 + 36 = 666.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (19681651831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 505125 + ... + 542691.

Almost surely, 2^19681651836 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19681651836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32737356288).

19681651836 is an abundant number, since it is smaller than the sum of its proper divisors (45793060740).

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

19681651836 is a wasteful number, since it uses less digits than its factorization.

19681651836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37611 (or 37590 counting only the distinct ones).

The product of its digits is 1866240, while the sum is 54.

The spelling of 19681651836 in words is "nineteen billion, six hundred eighty-one million, six hundred fifty-one thousand, eight hundred thirty-six".