21688354 has 8 divisors (see below), whose sum is σ = 32598720. Its totient is φ = 10822116.

The previous prime is 21688343. The next prime is 21688391. The reversal of 21688354 is 45388612.

It is a happy number.

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9774 + ... + 11785.

It is an arithmetic number, because the mean of its divisors is an integer number (4074840).

Almost surely, 2^21688354 is an apocalyptic number.

21688354 is a deficient number, since it is larger than the sum of its proper divisors (10910366).

21688354 is a wasteful number, since it uses less digits than its factorization.

21688354 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 22064.

The product of its digits is 46080, while the sum is 37.

The square root of 21688354 is about 4657.0756918908. The cubic root of 21688354 is about 278.8745383841.

The spelling of 21688354 in words is "twenty-one million, six hundred eighty-eight thousand, three hundred fifty-four".