21731703840 has 1728 divisors, whose sum is σ = 105030027648. Its totient is φ = 4180377600.

The previous prime is 21731703811. The next prime is 21731703883. The reversal of 21731703840 is 4830713712.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 21731703795 and 21731703804.

It is a congruent number.

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 287 ways as a sum of consecutive naturals, for example, 356257410 + ... + 356257470.

It is an arithmetic number, because the mean of its divisors is an integer number (60781266).

Almost surely, 2^21731703840 is an apocalyptic number.

21731703840 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 21731703840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (52515013824).

21731703840 is an abundant number, since it is smaller than the sum of its proper divisors (83298323808).

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

21731703840 is a wasteful number, since it uses less digits than its factorization.

21731703840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 133 (or 106 counting only the distinct ones).

The product of its (nonzero) digits is 28224, while the sum is 36.

The spelling of 21731703840 in words is "twenty-one billion, seven hundred thirty-one million, seven hundred three thousand, eight hundred forty".