21689144 has 32 divisors (see below), whose sum is σ = 43513200. Its totient is φ = 10099200.

The previous prime is 21689131. The next prime is 21689149. The reversal of 21689144 is 44198612.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21689149) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12947 + ... + 14525.

Almost surely, 2^21689144 is an apocalyptic number.

It is an amenable number.

21689144 is an abundant number, since it is smaller than the sum of its proper divisors (21824056).

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

21689144 is a wasteful number, since it uses less digits than its factorization.

21689144 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1703 (or 1699 counting only the distinct ones).

The product of its digits is 13824, while the sum is 35.

The square root of 21689144 is about 4657.1605082926. The cubic root of 21689144 is about 278.8779243520.

The spelling of 21689144 in words is "twenty-one million, six hundred eighty-nine thousand, one hundred forty-four".