21036842 has 16 divisors (see below), whose sum is σ = 32076000. Its totient is φ = 10346448.

The previous prime is 21036833. The next prime is 21036877. The reversal of 21036842 is 24863012.

It is an unprimeable number.

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, 41909 + ... + 42407.

It is an arithmetic number, because the mean of its divisors is an integer number (2004750).

Almost surely, 2^21036842 is an apocalyptic number.

21036842 is a deficient number, since it is larger than the sum of its proper divisors (11039158).

21036842 is a wasteful number, since it uses less digits than its factorization.

21036842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 805.

The product of its (nonzero) digits is 2304, while the sum is 26.

The square root of 21036842 is about 4586.5937251952. The cubic root of 21036842 is about 276.0536635134.

Adding to 21036842 its reverse (24863012), we get a palindrome (45899854).

The spelling of 21036842 in words is "twenty-one million, thirty-six thousand, eight hundred forty-two".