19844457864 has 144 divisors (see below), whose sum is σ = 63434775600. Its totient is φ = 5154367680.

The previous prime is 19844457859. The next prime is 19844457887. The reversal of 19844457864 is 46875444891.

It is a junction number, because it is equal to n+sod(n) for n = 19844457798 and 19844457807.

It is an unprimeable number.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 72567 + ... + 212025.

It is an arithmetic number, because the mean of its divisors is an integer number (440519275).

Almost surely, 2^19844457864 is an apocalyptic number.

19844457864 is a gapful number since it is divisible by the number (14) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 19844457864, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31717387800).

19844457864 is an abundant number, since it is smaller than the sum of its proper divisors (43590317736).

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

19844457864 is a wasteful number, since it uses less digits than its factorization.

19844457864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139504 (or 139482 counting only the distinct ones).

The product of its digits is 30965760, while the sum is 60.

The spelling of 19844457864 in words is "nineteen billion, eight hundred forty-four million, four hundred fifty-seven thousand, eight hundred sixty-four".