21680334 has 36 divisors (see below), whose sum is σ = 50872536. Its totient is φ = 6669936.

The previous prime is 21680327. The next prime is 21680341. The reversal of 21680334 is 43308612.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (21680327) and next prime (21680341).

It is a junction number, because it is equal to n+sod(n) for n = 21680298 and 21680307.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 522 + ... + 6605.

It is an arithmetic number, because the mean of its divisors is an integer number (1413126).

Almost surely, 2^21680334 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21680334, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25436268).

21680334 is an abundant number, since it is smaller than the sum of its proper divisors (29192202).

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

21680334 is a wasteful number, since it uses less digits than its factorization.

21680334 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7161 (or 7145 counting only the distinct ones).

The product of its (nonzero) digits is 3456, while the sum is 27.

The square root of 21680334 is about 4656.2145569121. The cubic root of 21680334 is about 278.8401597258.

Adding to 21680334 its reverse (43308612), we get a palindrome (64988946).

The spelling of 21680334 in words is "twenty-one million, six hundred eighty thousand, three hundred thirty-four".