19955001856 has 80 divisors (see below), whose sum is σ = 40545786600. Its totient is φ = 9809952768.

The previous prime is 19955001841. The next prime is 19955001887. The reversal of 19955001856 is 65810055991.

It can be written as a sum of positive squares in 4 ways, for example, as 6144051456 + 13810950400 = 78384^2 + 117520^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8793490 + ... + 8795758.

Almost surely, 2^19955001856 is an apocalyptic number.

19955001856 is a gapful number since it is divisible by the number (16) 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 19955001856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (20272893300).

19955001856 is an abundant number, since it is smaller than the sum of its proper divisors (20590784744).

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

19955001856 is an equidigital number, since it uses as much as digits as its factorization.

19955001856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2569 (or 2553 counting only the distinct ones).

The product of its (nonzero) digits is 486000, while the sum is 49.

The spelling of 19955001856 in words is "nineteen billion, nine hundred fifty-five million, one thousand, eight hundred fifty-six".