21682680 has 64 divisors (see below), whose sum is σ = 65728800. Its totient is φ = 5721600.

The previous prime is 21682673. The next prime is 21682681. The reversal of 21682680 is 8628612.

It is a super-2 number, since 2×21682680² = 940277223964800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21682681) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 11226 + ... + 13014.

Almost surely, 2^21682680 is an apocalyptic number.

21682680 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 21682680, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32864400).

21682680 is an abundant number, since it is smaller than the sum of its proper divisors (44046120).

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

21682680 is a wasteful number, since it uses less digits than its factorization.

21682680 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1904 (or 1900 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 33.

The square root of 21682680 is about 4656.4664714781. The cubic root of 21682680 is about 278.8502170035.

The spelling of 21682680 in words is "twenty-one million, six hundred eighty-two thousand, six hundred eighty".