21519991872000 has 800 divisors, whose sum is σ = 81476234343504. Its totient is φ = 5644505088000.

The previous prime is 21519991871993. The next prime is 21519991872013. The reversal of 21519991872000 is 27819991512.

It is a happy number.

21519991872000 is a `hidden beast` number, since 2 + 1 + 519 + 99 + 18 + 7 + 20 + 0 + 0 = 666.

It can be written as a sum of positive squares in 8 ways, for example, as 1671042265344 + 19848949606656 = 1292688^2 + 4455216^2 .

It is a tau number, because it is divible by the number of its divisors (800).

It is a super-2 number, since 2×21519991872000² (a number of 27 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 316189974 + ... + 316258026.

Almost surely, 2^{21519991872000} is an apocalyptic number.

21519991872000 is a gapful number since it is divisible by the number (20) 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 21519991872000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (40738117171752).

21519991872000 is an abundant number, since it is smaller than the sum of its proper divisors (59956242471504).

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

21519991872000 is an frugal number, since it uses more digits than its factorization.

21519991872000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68159 (or 68124 counting only the distinct ones).

The product of its (nonzero) digits is 816480, while the sum is 54.

The spelling of 21519991872000 in words is "twenty-one trillion, five hundred nineteen billion, nine hundred ninety-one million, eight hundred seventy-two thousand".