19971535872 has 176 divisors, whose sum is σ = 54473126400. Its totient is φ = 6503424000.

The previous prime is 19971535867. The next prime is 19971535891. The reversal of 19971535872 is 27853517991.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 45493029 + ... + 45493467.

It is an arithmetic number, because the mean of its divisors is an integer number (309506400).

Almost surely, 2^19971535872 is an apocalyptic number.

19971535872 is a gapful number since it is divisible by the number (12) 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 19971535872, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27236563200).

19971535872 is an abundant number, since it is smaller than the sum of its proper divisors (34501590528).

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

19971535872 is a wasteful number, since it uses less digits than its factorization.

19971535872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 772 (or 754 counting only the distinct ones).

The product of its digits is 4762800, while the sum is 57.

The spelling of 19971535872 in words is "nineteen billion, nine hundred seventy-one million, five hundred thirty-five thousand, eight hundred seventy-two".