19865008800 has 432 divisors, whose sum is σ = 86216981760. Its totient is φ = 4191160320.

The previous prime is 19865008781. The next prime is 19865008819. The reversal of 19865008800 is 880056891.

It is an interprime number because it is at equal distance from previous prime (19865008781) and next prime (19865008819).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 640041 + ... + 670359.

Almost surely, 2^19865008800 is an apocalyptic number.

19865008800 is a gapful number since it is divisible by the number (10) 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 19865008800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (43108490880).

19865008800 is an abundant number, since it is smaller than the sum of its proper divisors (66351972960).

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

19865008800 is a wasteful number, since it uses less digits than its factorization.

19865008800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 30365 (or 30349 counting only the distinct ones).

The product of its (nonzero) digits is 138240, while the sum is 45.

The spelling of 19865008800 in words is "nineteen billion, eight hundred sixty-five million, eight thousand, eight hundred".