21056834 has 8 divisors (see below), whose sum is σ = 32103228. Its totient is φ = 10355760.

The previous prime is 21056831. The next prime is 21056839. The reversal of 21056834 is 43865012.

It can be written as a sum of positive squares in 2 ways, for example, as 13300609 + 7756225 = 3647^2 + 2785^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a junction number, because it is equal to n+sod(n) for n = 21056797 and 21056806.

It is not an unprimeable number, because it can be changed into a prime (21056831) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 86177 + ... + 86420.

Almost surely, 2^21056834 is an apocalyptic number.

21056834 is a deficient number, since it is larger than the sum of its proper divisors (11046394).

21056834 is a wasteful number, since it uses less digits than its factorization.

21056834 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172660.

The product of its (nonzero) digits is 5760, while the sum is 29.

The square root of 21056834 is about 4588.7726027773. The cubic root of 21056834 is about 276.1410834394.

Subtracting from 21056834 its sum of digits (29), we obtain a triangular number (21056805 = T₆₄₈₉).

The spelling of 21056834 in words is "twenty-one million, fifty-six thousand, eight hundred thirty-four".