21090036 has 24 divisors (see below), whose sum is σ = 53684064. Its totient is φ = 6390880.

The previous prime is 21090007. The next prime is 21090061. The reversal of 21090036 is 63009012.

21090036 = T₃₅₉ + T₃₆₀ + ... + T₅₅₆.

It is a junction number, because it is equal to n+sod(n) for n = 21089994 and 21090021.

It is a congruent number.

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, 79755 + ... + 80018.

It is an arithmetic number, because the mean of its divisors is an integer number (2236836).

Almost surely, 2^21090036 is an apocalyptic number.

It is an amenable number.

21090036 is an abundant number, since it is smaller than the sum of its proper divisors (32594028).

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

21090036 is a wasteful number, since it uses less digits than its factorization.

21090036 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159791 (or 159789 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 21.

The square root of 21090036 is about 4592.3889208123. The cubic root of 21090036 is about 276.2861451582.

Adding to 21090036 its reverse (63009012), we get a palindrome (84099048).

The spelling of 21090036 in words is "twenty-one million, ninety thousand, thirty-six".