19727857440 has 144 divisors (see below), whose sum is σ = 67572905400. Its totient is φ = 5241102336.

The previous prime is 19727857403. The next prime is 19727857477. The reversal of 19727857440 is 4475872791.

19727857440 is a `hidden beast` number, since 1 + 9 + 7 + 27 + 8 + 574 + 40 = 666.

It is an interprime number because it is at equal distance from previous prime (19727857403) and next prime (19727857477).

It can be written as a sum of positive squares in 4 ways, for example, as 5702666256 + 14025191184 = 75516^2 + 118428^2 .

It is a tau number, because it is divible by the number of its divisors (144).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 361896 + ... + 412824.

Almost surely, 2^19727857440 is an apocalyptic number.

19727857440 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 19727857440, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33786452700).

19727857440 is an abundant number, since it is smaller than the sum of its proper divisors (47845047960).

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

19727857440 is a wasteful number, since it uses less digits than its factorization.

19727857440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51219 (or 51208 counting only the distinct ones).

The product of its (nonzero) digits is 3951360, while the sum is 54.

The spelling of 19727857440 in words is "nineteen billion, seven hundred twenty-seven million, eight hundred fifty-seven thousand, four hundred forty".