21608234 has 4 divisors (see below), whose sum is σ = 32412354. Its totient is φ = 10804116.

The previous prime is 21608233. The next prime is 21608239. The reversal of 21608234 is 43280612.

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., 21114025 + 494209 = 4595^2 + 703^2 .

It is not an unprimeable number, because it can be changed into a prime (21608233) 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 as a sum of consecutive naturals, namely, 5402057 + ... + 5402060.

Almost surely, 2^21608234 is an apocalyptic number.

21608234 is a deficient number, since it is larger than the sum of its proper divisors (10804120).

21608234 is a wasteful number, since it uses less digits than its factorization.

21608234 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10804119.

The product of its (nonzero) digits is 2304, while the sum is 26.

The square root of 21608234 is about 4648.4657684014. The cubic root of 21608234 is about 278.5307133382.

Adding to 21608234 its reverse (43280612), we get a palindrome (64888846).

The spelling of 21608234 in words is "twenty-one million, six hundred eight thousand, two hundred thirty-four".