21385686 has 32 divisors (see below), whose sum is σ = 49190400. Its totient is φ = 6071616.

The previous prime is 21385681. The next prime is 21385703. The reversal of 21385686 is 68658312.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21385681) 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, 5490 + ... + 8538.

It is an arithmetic number, because the mean of its divisors is an integer number (1537200).

Almost surely, 2^21385686 is an apocalyptic number.

21385686 is an abundant number, since it is smaller than the sum of its proper divisors (27804714).

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

21385686 is a wasteful number, since it uses less digits than its factorization.

21385686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3228.

The product of its digits is 69120, while the sum is 39.

The square root of 21385686 is about 4624.4660232291. The cubic root of 21385686 is about 277.5711951082.

The spelling of 21385686 in words is "twenty-one million, three hundred eighty-five thousand, six hundred eighty-six".