21434688 has 168 divisors, whose sum is σ = 71323200. Its totient is φ = 6082560.

The previous prime is 21434681. The next prime is 21434719. The reversal of 21434688 is 88643412.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21434681) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 107613 + ... + 107811.

Almost surely, 2^21434688 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21434688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (35661600).

21434688 is an abundant number, since it is smaller than the sum of its proper divisors (49888512).

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

21434688 is a wasteful number, since it uses less digits than its factorization.

21434688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 245 (or 232 counting only the distinct ones).

The product of its digits is 36864, while the sum is 36.

The square root of 21434688 is about 4629.7611169476. The cubic root of 21434688 is about 277.7830372456.

It can be divided in two parts, 21434 and 688, that added together give a palindrome (22122).

The spelling of 21434688 in words is "twenty-one million, four hundred thirty-four thousand, six hundred eighty-eight".