21056847 has 16 divisors (see below), whose sum is σ = 32693760. Its totient is φ = 11804832.

The previous prime is 21056839. The next prime is 21056869. The reversal of 21056847 is 74865012.

It is not a de Polignac number, because 21056847 - 2³ = 21056839 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21056447) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 8347 + ... + 10572.

It is an arithmetic number, because the mean of its divisors is an integer number (2043360).

Almost surely, 2^21056847 is an apocalyptic number.

21056847 is a deficient number, since it is larger than the sum of its proper divisors (11636913).

21056847 is a wasteful number, since it uses less digits than its factorization.

21056847 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18982.

The product of its (nonzero) digits is 13440, while the sum is 33.

The square root of 21056847 is about 4588.7740192779. The cubic root of 21056847 is about 276.1411402671.

The spelling of 21056847 in words is "twenty-one million, fifty-six thousand, eight hundred forty-seven".