19491916800 has 132 divisors (see below), whose sum is σ = 64422054056. Its totient is φ = 5197824000.

The previous prime is 19491916799. The next prime is 19491916811. The reversal of 19491916800 is 861919491.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 19491916800.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 50101 + ... + 203700.

Almost surely, 2^19491916800 is an apocalyptic number.

19491916800 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 19491916800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32211027028).

19491916800 is an abundant number, since it is smaller than the sum of its proper divisors (44930137256).

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

19491916800 is a wasteful number, since it uses less digits than its factorization.

19491916800 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 253834 (or 253811 counting only the distinct ones).

The product of its (nonzero) digits is 139968, while the sum is 48.

The spelling of 19491916800 in words is "nineteen billion, four hundred ninety-one million, nine hundred sixteen thousand, eight hundred".