21683340 has 72 divisors (see below), whose sum is σ = 75173280. Its totient is φ = 4955904.

The previous prime is 21683339. The next prime is 21683359. The reversal of 21683340 is 4338612.

It is a happy number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 7345 + ... + 9864.

Almost surely, 2^21683340 is an apocalyptic number.

21683340 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21683340 is an abundant number, since it is smaller than the sum of its proper divisors (53489940).

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

21683340 is a wasteful number, since it uses less digits than its factorization.

21683340 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17231 (or 17226 counting only the distinct ones).

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

The square root of 21683340 is about 4656.5373401273. The cubic root of 21683340 is about 278.8530462859.

The spelling of 21683340 in words is "twenty-one million, six hundred eighty-three thousand, three hundred forty".