21681262 has 8 divisors (see below), whose sum is σ = 32664600. Its totient is φ = 10793064.

The previous prime is 21681221. The next prime is 21681269. The reversal of 21681262 is 26218612.

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

It is a self number, because there is not a number n which added to its sum of digits gives 21681262.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21681269) 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 3 ways as a sum of consecutive naturals, for example, 23212 + ... + 24127.

It is an arithmetic number, because the mean of its divisors is an integer number (4083075).

Almost surely, 2^21681262 is an apocalyptic number.

21681262 is a deficient number, since it is larger than the sum of its proper divisors (10983338).

21681262 is a wasteful number, since it uses less digits than its factorization.

21681262 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47570.

The product of its digits is 2304, while the sum is 28.

The square root of 21681262 is about 4656.3142076110. The cubic root of 21681262 is about 278.8441381389.

Adding to 21681262 its reverse (26218612), we get a palindrome (47899874).

The spelling of 21681262 in words is "twenty-one million, six hundred eighty-one thousand, two hundred sixty-two".