21422688 has 96 divisors (see below), whose sum is σ = 65318400. Its totient is φ = 6021120.

The previous prime is 21422641. The next prime is 21422689. The reversal of 21422688 is 88622412.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (96).

It is a super-2 number, since 2×21422688² = 917863122290688, which contains 22 as substring.

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 (21422689) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 47488 + ... + 47936.

It is an arithmetic number, because the mean of its divisors is an integer number (680400).

Almost surely, 2^21422688 is an apocalyptic number.

21422688 is a gapful number since it is divisible by the number (28) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21422688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (32659200).

21422688 is an abundant number, since it is smaller than the sum of its proper divisors (43895712).

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

21422688 is a wasteful number, since it uses less digits than its factorization.

21422688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 540 (or 532 counting only the distinct ones).

The product of its digits is 12288, while the sum is 33.

The square root of 21422688 is about 4628.4649723207. The cubic root of 21422688 is about 277.7311895319.

The spelling of 21422688 in words is "twenty-one million, four hundred twenty-two thousand, six hundred eighty-eight".