21859738 has 16 divisors (see below), whose sum is σ = 33786720. Its totient is φ = 10601136.

The previous prime is 21859723. The next prime is 21859741. The reversal of 21859738 is 83795812.

It is a Harshad number since it is a multiple of its sum of digits (43).

It is a junction number, because it is equal to n+sod(n) for n = 21859694 and 21859703.

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 7 ways as a sum of consecutive naturals, for example, 12693 + ... + 14311.

It is an arithmetic number, because the mean of its divisors is an integer number (2111670).

Almost surely, 2^21859738 is an apocalyptic number.

21859738 is a deficient number, since it is larger than the sum of its proper divisors (11926982).

21859738 is a wasteful number, since it uses less digits than its factorization.

21859738 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1821.

The product of its digits is 120960, while the sum is 43.

The square root of 21859738 is about 4675.4398723543. The cubic root of 21859738 is about 279.6071787476.

The spelling of 21859738 in words is "twenty-one million, eight hundred fifty-nine thousand, seven hundred thirty-eight".