21686414 has 4 divisors (see below), whose sum is σ = 32529624. Its totient is φ = 10843206.

The previous prime is 21686389. The next prime is 21686419. The reversal of 21686414 is 41468612.

It is a semiprime because it is the product of two primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21686419) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5421602 + ... + 5421605.

It is an arithmetic number, because the mean of its divisors is an integer number (8132406).

Almost surely, 2^21686414 is an apocalyptic number.

21686414 is a deficient number, since it is larger than the sum of its proper divisors (10843210).

21686414 is a wasteful number, since it uses less digits than its factorization.

21686414 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10843209.

The product of its digits is 9216, while the sum is 32.

The square root of 21686414 is about 4656.8674020204. The cubic root of 21686414 is about 278.8662231268.

The spelling of 21686414 in words is "twenty-one million, six hundred eighty-six thousand, four hundred fourteen".