21871581340 has 384 divisors, whose sum is σ = 60060672000. Its totient is φ = 6521389056.

The previous prime is 21871581317. The next prime is 21871581349. The reversal of 21871581340 is 4318517812.

It is a junction number, because it is equal to n+sod(n) for n = 21871581293 and 21871581302.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21871581349) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 225480172 + ... + 225480268.

It is an arithmetic number, because the mean of its divisors is an integer number (156408000).

Almost surely, 2^21871581340 is an apocalyptic number.

21871581340 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 21871581340, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (30030336000).

21871581340 is an abundant number, since it is smaller than the sum of its proper divisors (38189090660).

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

21871581340 is a wasteful number, since it uses less digits than its factorization.

21871581340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 277 (or 275 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 40.

The spelling of 21871581340 in words is "twenty-one billion, eight hundred seventy-one million, five hundred eighty-one thousand, three hundred forty".