21786891744 has 96 divisors (see below), whose sum is σ = 58784727456. Its totient is φ = 7060193280.

The previous prime is 21786891673. The next prime is 21786891751. The reversal of 21786891744 is 44719868712.

It is a tau number, because it is divible by the number of its divisors (96).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7162864 + ... + 7165904.

It is an arithmetic number, because the mean of its divisors is an integer number (612340911).

Almost surely, 2^21786891744 is an apocalyptic number.

21786891744 is a gapful number since it is divisible by the number (24) 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 21786891744, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (29392363728).

21786891744 is an abundant number, since it is smaller than the sum of its proper divisors (36997835712).

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

21786891744 is a wasteful number, since it uses less digits than its factorization.

21786891744 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5108 (or 5100 counting only the distinct ones).

The product of its digits is 5419008, while the sum is 57.

The spelling of 21786891744 in words is "twenty-one billion, seven hundred eighty-six million, eight hundred ninety-one thousand, seven hundred forty-four".