21102885 has 12 divisors (see below), whose sum is σ = 36578412. Its totient is φ = 11254848.

The previous prime is 21102883. The next prime is 21102911. The reversal of 21102885 is 58820112.

It can be written as a sum of positive squares in 2 ways, for example, as 4186116 + 16916769 = 2046^2 + 4113^2 .

It is not a de Polignac number, because 21102885 - 2¹ = 21102883 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21102883) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 234432 + ... + 234521.

It is an arithmetic number, because the mean of its divisors is an integer number (3048201).

Almost surely, 2^21102885 is an apocalyptic number.

It is an amenable number.

21102885 is a deficient number, since it is larger than the sum of its proper divisors (15475527).

21102885 is a wasteful number, since it uses less digits than its factorization.

21102885 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 468964 (or 468961 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 27.

The square root of 21102885 is about 4593.7876529069. The cubic root of 21102885 is about 276.3422424227.

Adding to 21102885 its reverse (58820112), we get a palindrome (79922997).

The spelling of 21102885 in words is "twenty-one million, one hundred two thousand, eight hundred eighty-five".