21026536 has 16 divisors (see below), whose sum is σ = 39788100. Its totient is φ = 10416384.

The previous prime is 21026519. The next prime is 21026549. The reversal of 21026536 is 63562012.

It can be written as a sum of positive squares in 2 ways, for example, as 20304036 + 722500 = 4506^2 + 850^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21026536.

It is an unprimeable number.

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, 11185 + ... + 12928.

Almost surely, 2^21026536 is an apocalyptic number.

It is an amenable number.

21026536 is a deficient number, since it is larger than the sum of its proper divisors (18761564).

21026536 is a wasteful number, since it uses less digits than its factorization.

21026536 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24228 (or 24224 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 25.

The square root of 21026536 is about 4585.4700958571. The cubic root of 21026536 is about 276.0085763631.

Adding to 21026536 its reverse (63562012), we get a palindrome (84588548).

The spelling of 21026536 in words is "twenty-one million, twenty-six thousand, five hundred thirty-six".