21112261 has 8 divisors (see below), whose sum is σ = 21984120. Its totient is φ = 20250048.

The previous prime is 21112241. The next prime is 21112279. The reversal of 21112261 is 16221112.

It can be written as a sum of positive squares in 4 ways, for example, as 591361 + 20520900 = 769^2 + 4530^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 21112261 - 2⁹ = 21111749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21112241) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 2235 + ... + 6871.

It is an arithmetic number, because the mean of its divisors is an integer number (2748015).

Almost surely, 2^21112261 is an apocalyptic number.

It is an amenable number.

21112261 is a deficient number, since it is larger than the sum of its proper divisors (871859).

21112261 is a wasteful number, since it uses less digits than its factorization.

21112261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4823.

The product of its digits is 48, while the sum is 16.

The square root of 21112261 is about 4594.8080482214. The cubic root of 21112261 is about 276.3831625976.

Adding to 21112261 its reverse (16221112), we get a palindrome (37333373).

The spelling of 21112261 in words is "twenty-one million, one hundred twelve thousand, two hundred sixty-one".