21056735 has 16 divisors (see below), whose sum is σ = 28994112. Its totient is φ = 14380800.

The previous prime is 21056723. The next prime is 21056743. The reversal of 21056735 is 53765012.

It is not a de Polignac number, because 21056735 - 2⁶ = 21056671 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21056698 and 21056707.

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 15 ways as a sum of consecutive naturals, for example, 8765 + ... + 10905.

It is an arithmetic number, because the mean of its divisors is an integer number (1812132).

Almost surely, 2^21056735 is an apocalyptic number.

21056735 is a deficient number, since it is larger than the sum of its proper divisors (7937377).

21056735 is a wasteful number, since it uses less digits than its factorization.

21056735 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2434.

The product of its (nonzero) digits is 6300, while the sum is 29.

The square root of 21056735 is about 4588.7618155664. The cubic root of 21056735 is about 276.1406506739.

The spelling of 21056735 in words is "twenty-one million, fifty-six thousand, seven hundred thirty-five".