21245814 has 40 divisors (see below), whose sum is σ = 47872440. Its totient is φ = 7042464.

The previous prime is 21245803. The next prime is 21245839. The reversal of 21245814 is 41854212.

It is a super-2 number, since 2×21245814² = 902769225045192, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a congruent number.

It is an unprimeable number.

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 19 ways as a sum of consecutive naturals, for example, 50497 + ... + 50915.

It is an arithmetic number, because the mean of its divisors is an integer number (1196811).

Almost surely, 2^21245814 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21245814, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23936220).

21245814 is an abundant number, since it is smaller than the sum of its proper divisors (26626626).

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

21245814 is a wasteful number, since it uses less digits than its factorization.

21245814 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 746 (or 737 counting only the distinct ones).

The product of its digits is 2560, while the sum is 27.

The square root of 21245814 is about 4609.3181708361. The cubic root of 21245814 is about 276.9647241850.

The spelling of 21245814 in words is "twenty-one million, two hundred forty-five thousand, eight hundred fourteen".