21566341 has 4 divisors (see below), whose sum is σ = 22504032. Its totient is φ = 20628652.

The previous prime is 21566339. The next prime is 21566351. The reversal of 21566341 is 14366512.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21566341 - 2¹ = 21566339 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 (21566351) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 468811 + ... + 468856.

It is an arithmetic number, because the mean of its divisors is an integer number (5626008).

Almost surely, 2^21566341 is an apocalyptic number.

It is an amenable number.

21566341 is a deficient number, since it is larger than the sum of its proper divisors (937691).

21566341 is an equidigital number, since it uses as much as digits as its factorization.

21566341 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 937690.

The product of its digits is 4320, while the sum is 28.

The square root of 21566341 is about 4643.9574718122. The cubic root of 21566341 is about 278.3505962576.

The spelling of 21566341 in words is "twenty-one million, five hundred sixty-six thousand, three hundred forty-one".