21568234 has 4 divisors (see below), whose sum is σ = 32352354. Its totient is φ = 10784116.

The previous prime is 21568229. The next prime is 21568243. The reversal of 21568234 is 43286512.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 20675209 + 893025 = 4547^2 + 945^2 .

It is a Smith number, since the sum of its digits (31) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a junction number, because it is equal to n+sod(n) for n = 21568196 and 21568205.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5392057 + ... + 5392060.

Almost surely, 2^21568234 is an apocalyptic number.

21568234 is a deficient number, since it is larger than the sum of its proper divisors (10784120).

21568234 is a wasteful number, since it uses less digits than its factorization.

21568234 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10784119.

The product of its digits is 11520, while the sum is 31.

The square root of 21568234 is about 4644.1612805759. The cubic root of 21568234 is about 278.3587401559.

The spelling of 21568234 in words is "twenty-one million, five hundred sixty-eight thousand, two hundred thirty-four".