21530434 has 4 divisors (see below), whose sum is σ = 32295654. Its totient is φ = 10765216.

The previous prime is 21530413. The next prime is 21530447. The reversal of 21530434 is 43403512.

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., 10870209 + 10660225 = 3297^2 + 3265^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5382607 + ... + 5382610.

Almost surely, 2^21530434 is an apocalyptic number.

21530434 is a deficient number, since it is larger than the sum of its proper divisors (10765220).

21530434 is a wasteful number, since it uses less digits than its factorization.

21530434 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10765219.

The product of its (nonzero) digits is 1440, while the sum is 22.

The square root of 21530434 is about 4640.0898698193. The cubic root of 21530434 is about 278.1960299834.

Adding to 21530434 its reverse (43403512), we get a palindrome (64933946).

The spelling of 21530434 in words is "twenty-one million, five hundred thirty thousand, four hundred thirty-four".