21680858 has 32 divisors (see below), whose sum is σ = 35392896. Its totient is φ = 9934848.

The previous prime is 21680849. The next prime is 21680861. The reversal of 21680858 is 85808612.

It is an unprimeable number.

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, 191810 + ... + 191922.

It is an arithmetic number, because the mean of its divisors is an integer number (1106028).

Almost surely, 2^21680858 is an apocalyptic number.

21680858 is a deficient number, since it is larger than the sum of its proper divisors (13712038).

21680858 is a wasteful number, since it uses less digits than its factorization.

21680858 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 278.

The product of its (nonzero) digits is 30720, while the sum is 38.

The square root of 21680858 is about 4656.2708254568. The cubic root of 21680858 is about 278.8424061713.

The spelling of 21680858 in words is "twenty-one million, six hundred eighty thousand, eight hundred fifty-eight".