19891011840 has 1152 divisors, whose sum is σ = 84768768000. Its totient is φ = 3864526848.

The previous prime is 19891011773. The next prime is 19891011901. The reversal of 19891011840 is 4811019891.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 19891011792 and 19891011801.

It is an unprimeable number.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 251784921 + ... + 251784999.

It is an arithmetic number, because the mean of its divisors is an integer number (73584000).

Almost surely, 2^19891011840 is an apocalyptic number.

19891011840 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 19891011840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42384384000).

19891011840 is an abundant number, since it is smaller than the sum of its proper divisors (64877756160).

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

19891011840 is a wasteful number, since it uses less digits than its factorization.

19891011840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 175 (or 161 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 42.

The spelling of 19891011840 in words is "nineteen billion, eight hundred ninety-one million, eleven thousand, eight hundred forty".