21056535 has 24 divisors (see below), whose sum is σ = 36610704. Its totient is φ = 11195520.

The previous prime is 21056527. The next prime is 21056537. The reversal of 21056535 is 53565012.

21056535 is a `hidden beast` number, since 2 + 1 + 0 + 5 + 653 + 5 = 666.

It is not a de Polignac number, because 21056535 - 2³ = 21056527 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21056499 and 21056508.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21056537) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 21619 + ... + 22571.

It is an arithmetic number, because the mean of its divisors is an integer number (1525446).

Almost surely, 2^21056535 is an apocalyptic number.

21056535 is a deficient number, since it is larger than the sum of its proper divisors (15554169).

21056535 is a wasteful number, since it uses less digits than its factorization.

21056535 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1455 (or 1452 counting only the distinct ones).

The product of its (nonzero) digits is 4500, while the sum is 27.

The square root of 21056535 is about 4588.7400231436. The cubic root of 21056535 is about 276.1397763962.

The spelling of 21056535 in words is "twenty-one million, fifty-six thousand, five hundred thirty-five".