21685134 has 32 divisors (see below), whose sum is σ = 44461440. Its totient is φ = 7048800.

The previous prime is 21685133. The next prime is 21685163. The reversal of 21685134 is 43158612.

21685134 is a Rhonda number in base 10.

Its product of digits (5760) is a multiple of the sum of its prime divisors (576).

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21685133) 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 15 ways as a sum of consecutive naturals, for example, 65349 + ... + 65679.

It is an arithmetic number, because the mean of its divisors is an integer number (1389420).

Almost surely, 2^21685134 is an apocalyptic number.

21685134 is an abundant number, since it is smaller than the sum of its proper divisors (22776306).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21685134 is a wasteful number, since it uses less digits than its factorization.

21685134 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 576.

The product of its digits is 5760, while the sum is 30.

The square root of 21685134 is about 4656.7299685509. The cubic root of 21685134 is about 278.8607364998.

The spelling of 21685134 in words is "twenty-one million, six hundred eighty-five thousand, one hundred thirty-four".