21536109 has 24 divisors (see below), whose sum is σ = 36516480. Its totient is φ = 11972448.

The previous prime is 21536107. The next prime is 21536113. The reversal of 21536109 is 90163512.

21536109 is a `hidden beast` number, since 21 + 536 + 109 = 666.

It is not a de Polignac number, because 21536109 - 2¹ = 21536107 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21536107) by changing a digit.

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 23 ways as a sum of consecutive naturals, for example, 2289 + ... + 6950.

It is an arithmetic number, because the mean of its divisors is an integer number (1521520).

Almost surely, 2^21536109 is an apocalyptic number.

It is an amenable number.

21536109 is a deficient number, since it is larger than the sum of its proper divisors (14980371).

21536109 is a wasteful number, since it uses less digits than its factorization.

21536109 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9289 (or 9286 counting only the distinct ones).

The product of its (nonzero) digits is 1620, while the sum is 27.

The square root of 21536109 is about 4640.7013478568. The cubic root of 21536109 is about 278.2204701748.

It can be divided in two parts, 21 and 536109, that added together give a triangular number (536130 = T₁₀₃₅).

The spelling of 21536109 in words is "twenty-one million, five hundred thirty-six thousand, one hundred nine".