21125842 has 8 divisors (see below), whose sum is σ = 32363136. Its totient is φ = 10338132.

The previous prime is 21125803. The next prime is 21125843. The reversal of 21125842 is 24852112.

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

It is not an unprimeable number, because it can be changed into a prime (21125843) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 112278 + ... + 112465.

It is an arithmetic number, because the mean of its divisors is an integer number (4045392).

Almost surely, 2^21125842 is an apocalyptic number.

21125842 is a deficient number, since it is larger than the sum of its proper divisors (11237294).

21125842 is a wasteful number, since it uses less digits than its factorization.

21125842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 224792.

The product of its digits is 1280, while the sum is 25.

The square root of 21125842 is about 4596.2856743244. The cubic root of 21125842 is about 276.4424133992.

Adding to 21125842 its reverse (24852112), we get a palindrome (45977954).

The spelling of 21125842 in words is "twenty-one million, one hundred twenty-five thousand, eight hundred forty-two".