21534361 has 4 divisors (see below), whose sum is σ = 21646132. Its totient is φ = 21422592.

The previous prime is 21534349. The next prime is 21534397. The reversal of 21534361 is 16343512.

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

It can be written as a sum of positive squares in 2 ways, for example, as 5494336 + 16040025 = 2344^2 + 4005^2 .

It is a cyclic number.

It is not a de Polignac number, because 21534361 - 2⁵ = 21534329 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21534301) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 55596 + ... + 55981.

It is an arithmetic number, because the mean of its divisors is an integer number (5411533).

Almost surely, 2^21534361 is an apocalyptic number.

It is an amenable number.

21534361 is a deficient number, since it is larger than the sum of its proper divisors (111771).

21534361 is a wasteful number, since it uses less digits than its factorization.

21534361 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 111770.

The product of its digits is 2160, while the sum is 25.

The square root of 21534361 is about 4640.5130104332. The cubic root of 21534361 is about 278.2129426228.

Adding to 21534361 its reverse (16343512), we get a palindrome (37877873).

The spelling of 21534361 in words is "twenty-one million, five hundred thirty-four thousand, three hundred sixty-one".