21105042 has 16 divisors (see below), whose sum is σ = 48240192. Its totient is φ = 6030000.

The previous prime is 21105023. The next prime is 21105043. The reversal of 21105042 is 24050112.

It is not an unprimeable number, because it can be changed into a prime (21105043) 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, 251209 + ... + 251292.

It is an arithmetic number, because the mean of its divisors is an integer number (3015012).

Almost surely, 2^21105042 is an apocalyptic number.

21105042 is an abundant number, since it is smaller than the sum of its proper divisors (27135150).

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

21105042 is a wasteful number, since it uses less digits than its factorization.

21105042 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 502513.

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21105042 is about 4594.0224204938. The cubic root of 21105042 is about 276.3516574057.

Adding to 21105042 its reverse (24050112), we get a palindrome (45155154).

The spelling of 21105042 in words is "twenty-one million, one hundred five thousand, forty-two".