19959865344 has 448 divisors, whose sum is σ = 63414005760. Its totient is φ = 6193152000.

The previous prime is 19959865339. The next prime is 19959865357. The reversal of 19959865344 is 44356895991.

19959865344 is a `hidden beast` number, since 1 + 9 + 9 + 5 + 98 + 6 + 534 + 4 = 666.

It is a super-2 number, since 2×19959865344² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 281124829 + ... + 281124899.

It is an arithmetic number, because the mean of its divisors is an integer number (141549120).

Almost surely, 2^19959865344 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 19959865344, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31707002880).

19959865344 is an abundant number, since it is smaller than the sum of its proper divisors (43454140416).

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

19959865344 is an equidigital number, since it uses as much as digits as its factorization.

19959865344 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 178 (or 148 counting only the distinct ones).

The product of its digits is 41990400, while the sum is 63.

The spelling of 19959865344 in words is "nineteen billion, nine hundred fifty-nine million, eight hundred sixty-five thousand, three hundred forty-four".