19818039837816 has 432 divisors, whose sum is σ = 61835152022280. Its totient is φ = 5686257984000.

The previous prime is 19818039837797. The next prime is 19818039837821. The reversal of 19818039837816 is 61873893081891.

19818039837816 is a `hidden beast` number, since 1 + 9 + 81 + 80 + 3 + 98 + 378 + 16 = 666.

It is a Harshad number since it is a multiple of its sum of digits (72).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 107 ways as a sum of consecutive naturals, for example, 4273890250 + ... + 4273894886.

Almost surely, 2^{19818039837816} 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 19818039837816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30917576011140).

19818039837816 is an abundant number, since it is smaller than the sum of its proper divisors (42017112184464).

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

19818039837816 is a wasteful number, since it uses less digits than its factorization.

19818039837816 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4908 (or 4777 counting only the distinct ones).

The product of its (nonzero) digits is 125411328, while the sum is 72.

The spelling of 19818039837816 in words is "nineteen trillion, eight hundred eighteen billion, thirty-nine million, eight hundred thirty-seven thousand, eight hundred sixteen".