19555445778 has 32 divisors (see below), whose sum is σ = 42685574400. Its totient is φ = 5923233360.

The previous prime is 19555445771. The next prime is 19555445783. The reversal of 19555445778 is 87754455591.

It is a happy number.

It is not an unprimeable number, because it can be changed into a prime (19555445771) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 84273 + ... + 214971.

It is an arithmetic number, because the mean of its divisors is an integer number (1333924200).

Almost surely, 2^19555445778 is an apocalyptic number.

19555445778 is an abundant number, since it is smaller than the sum of its proper divisors (23130128622).

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

19555445778 is a wasteful number, since it uses less digits than its factorization.

19555445778 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 132982.

The product of its digits is 35280000, while the sum is 60.

The spelling of 19555445778 in words is "nineteen billion, five hundred fifty-five million, four hundred forty-five thousand, seven hundred seventy-eight".