21500682840 has 384 divisors, whose sum is σ = 88008560640. Its totient is φ = 4430619648.

The previous prime is 21500682821. The next prime is 21500682899. The reversal of 21500682840 is 4828600512.

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 = 21500682795 and 21500682804.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 1401049 + ... + 1416311.

It is an arithmetic number, because the mean of its divisors is an integer number (229188960).

Almost surely, 2^21500682840 is an apocalyptic number.

21500682840 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 21500682840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (44004280320).

21500682840 is an abundant number, since it is smaller than the sum of its proper divisors (66507877800).

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

21500682840 is a wasteful number, since it uses less digits than its factorization.

21500682840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 15343 (or 15336 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 36.

The spelling of 21500682840 in words is "twenty-one billion, five hundred million, six hundred eighty-two thousand, eight hundred forty".