21426281 has 8 divisors (see below), whose sum is σ = 22674720. Its totient is φ = 20189952.

The previous prime is 21426277. The next prime is 21426287. The reversal of 21426281 is 18262412.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21426281 - 2² = 21426277 is a prime.

It is a super-2 number, since 2×21426281² = 918171034981922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21426281.

It is not an unprimeable number, because it can be changed into a prime (21426287) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 746 + ... + 6588.

It is an arithmetic number, because the mean of its divisors is an integer number (2834340).

Almost surely, 2^21426281 is an apocalyptic number.

It is an amenable number.

21426281 is a deficient number, since it is larger than the sum of its proper divisors (1248439).

21426281 is a wasteful number, since it uses less digits than its factorization.

21426281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 6055.

The product of its digits is 1536, while the sum is 26.

The square root of 21426281 is about 4628.8530976906. The cubic root of 21426281 is about 277.7467156318.

Adding to 21426281 its reverse (18262412), we get a palindrome (39688693).

The spelling of 21426281 in words is "twenty-one million, four hundred twenty-six thousand, two hundred eighty-one".