21682539840 has 224 divisors, whose sum is σ = 78499411200. Its totient is φ = 5023236096.

The previous prime is 21682539761. The next prime is 21682539877. The reversal of 21682539840 is 4893528612.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a self number, because there is not a number n which added to its sum of digits gives 21682539840.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 161061 + ... + 263259.

It is an arithmetic number, because the mean of its divisors is an integer number (350443800).

Almost surely, 2^21682539840 is an apocalyptic number.

21682539840 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 21682539840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (39249705600).

21682539840 is an abundant number, since it is smaller than the sum of its proper divisors (56816871360).

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

21682539840 is a wasteful number, since it uses less digits than its factorization.

21682539840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 102249 (or 102239 counting only the distinct ones).

The product of its (nonzero) digits is 829440, while the sum is 48.

The spelling of 21682539840 in words is "twenty-one billion, six hundred eighty-two million, five hundred thirty-nine thousand, eight hundred forty".