21427830 has 48 divisors (see below), whose sum is σ = 57081024. Its totient is φ = 5573760.

The previous prime is 21427829. The next prime is 21427841. The reversal of 21427830 is 3872412.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 21427794 and 21427803.

It is a congruent 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, 787 + ... + 6593.

It is an arithmetic number, because the mean of its divisors is an integer number (1189188).

Almost surely, 2^21427830 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21427830, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (28540512).

21427830 is an abundant number, since it is smaller than the sum of its proper divisors (35653194).

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

21427830 is a wasteful number, since it uses less digits than its factorization.

21427830 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5861 (or 5858 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 27.

The square root of 21427830 is about 4629.0204147314. The cubic root of 21427830 is about 277.7534086474.

The spelling of 21427830 in words is "twenty-one million, four hundred twenty-seven thousand, eight hundred thirty".