21679842 has 8 divisors (see below), whose sum is σ = 43359696. Its totient is φ = 7226612.

The previous prime is 21679829. The next prime is 21679843. The reversal of 21679842 is 24897612.

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

21679842 is an admirable number.

It is a self number, because there is not a number n which added to its sum of digits gives 21679842.

It is not an unprimeable number, because it can be changed into a prime (21679843) 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 3 ways as a sum of consecutive naturals, for example, 1806648 + ... + 1806659.

It is an arithmetic number, because the mean of its divisors is an integer number (5419962).

Almost surely, 2^21679842 is an apocalyptic number.

21679842 is a primitive abundant number, since it is smaller than the sum of its proper divisors, none of which is abundant.

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

21679842 is a wasteful number, since it uses less digits than its factorization.

21679842 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3613312.

The product of its digits is 48384, while the sum is 39.

The square root of 21679842 is about 4656.1617239954. The cubic root of 21679842 is about 278.8380504348.

The spelling of 21679842 in words is "twenty-one million, six hundred seventy-nine thousand, eight hundred forty-two".