19855311840 has 768 divisors, whose sum is σ = 90592266240. Its totient is φ = 3941498880.

The previous prime is 19855311803. The next prime is 19855311863. The reversal of 19855311840 is 4811355891.

19855311840 is a `hidden beast` number, since 1 + 9 + 8 + 553 + 11 + 84 + 0 = 666.

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

It is a congruent number.

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, 6681555 + ... + 6684525.

It is an arithmetic number, because the mean of its divisors is an integer number (117958680).

Almost surely, 2^19855311840 is an apocalyptic number.

19855311840 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 19855311840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (45296133120).

19855311840 is an abundant number, since it is smaller than the sum of its proper divisors (70736954400).

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

19855311840 is a wasteful number, since it uses less digits than its factorization.

19855311840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3032 (or 3018 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 45.

The spelling of 19855311840 in words is "nineteen billion, eight hundred fifty-five million, three hundred eleven thousand, eight hundred forty".