20522581 has 4 divisors (see below), whose sum is σ = 20734252. Its totient is φ = 20310912.

The previous prime is 20522549. The next prime is 20522609. The reversal of 20522581 is 18522502.

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 9400356 + 11122225 = 3066^2 + 3335^2 .

It is a cyclic number.

It is not a de Polignac number, because 20522581 - 2⁵ = 20522549 is a prime.

It is a super-2 number, since 2×20522581² = 842352661803122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20522521) 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, 105690 + ... + 105883.

It is an arithmetic number, because the mean of its divisors is an integer number (5183563).

Almost surely, 2^20522581 is an apocalyptic number.

It is an amenable number.

20522581 is a deficient number, since it is larger than the sum of its proper divisors (211671).

20522581 is an equidigital number, since it uses as much as digits as its factorization.

20522581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 211670.

The product of its (nonzero) digits is 1600, while the sum is 25.

The square root of 20522581 is about 4530.1855370393. The cubic root of 20522581 is about 273.7856360550.

The spelling of 20522581 in words is "twenty million, five hundred twenty-two thousand, five hundred eighty-one".