21859394 has 8 divisors (see below), whose sum is σ = 33551760. Its totient is φ = 10675476.

The previous prime is 21859393. The next prime is 21859403. The reversal of 21859394 is 49395812.

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

It is not an unprimeable number, because it can be changed into a prime (21859391) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 127004 + ... + 127175.

It is an arithmetic number, because the mean of its divisors is an integer number (4193970).

Almost surely, 2^21859394 is an apocalyptic number.

21859394 is a deficient number, since it is larger than the sum of its proper divisors (11692366).

21859394 is a wasteful number, since it uses less digits than its factorization.

21859394 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 254224.

The product of its digits is 77760, while the sum is 41.

The square root of 21859394 is about 4675.4030842271. The cubic root of 21859394 is about 279.6057120424.

The spelling of 21859394 in words is "twenty-one million, eight hundred fifty-nine thousand, three hundred ninety-four".