21413281 has 8 divisors (see below), whose sum is σ = 22867200. Its totient is φ = 20007120.

The previous prime is 21413279. The next prime is 21413297. The reversal of 21413281 is 18231412.

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 21413281 - 2¹ = 21413279 is a prime.

It is a super-2 number, since 2×21413281² = 917057206369922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21413221) by changing a digit.

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 7 ways as a sum of consecutive naturals, for example, 11011 + ... + 12808.

It is an arithmetic number, because the mean of its divisors is an integer number (2858400).

Almost surely, 2^21413281 is an apocalyptic number.

It is an amenable number.

21413281 is a deficient number, since it is larger than the sum of its proper divisors (1453919).

21413281 is a wasteful number, since it uses less digits than its factorization.

21413281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23879.

The product of its digits is 384, while the sum is 22.

The square root of 21413281 is about 4627.4486490938. The cubic root of 21413281 is about 277.6905317053.

Adding to 21413281 its reverse (18231412), we get a palindrome (39644693).

The spelling of 21413281 in words is "twenty-one million, four hundred thirteen thousand, two hundred eighty-one".