21683489 has 4 divisors (see below), whose sum is σ = 21694656. Its totient is φ = 21672324.

The previous prime is 21683437. The next prime is 21683491. The reversal of 21683489 is 98438612.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21683489 - 2¹² = 21679393 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21683419) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1829 + ... + 6834.

It is an arithmetic number, because the mean of its divisors is an integer number (5423664).

Almost surely, 2^21683489 is an apocalyptic number.

It is an amenable number.

21683489 is a deficient number, since it is larger than the sum of its proper divisors (11167).

21683489 is an equidigital number, since it uses as much as digits as its factorization.

21683489 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 11166.

The product of its digits is 82944, while the sum is 41.

The square root of 21683489 is about 4656.5533391125. The cubic root of 21683489 is about 278.8536850099.

The spelling of 21683489 in words is "twenty-one million, six hundred eighty-three thousand, four hundred eighty-nine".