20540261 has 6 divisors (see below), whose sum is σ = 23893830. Its totient is φ = 17605896.

The previous prime is 20540251. The next prime is 20540279. The reversal of 20540261 is 16204502.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 18232900 + 2307361 = 4270^2 + 1519^2 .

It is not a de Polignac number, because 20540261 - 2²² = 16345957 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 (20540231) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 209546 + ... + 209643.

It is an arithmetic number, because the mean of its divisors is an integer number (3982305).

Almost surely, 2^20540261 is an apocalyptic number.

It is an amenable number.

20540261 is a deficient number, since it is larger than the sum of its proper divisors (3353569).

20540261 is an equidigital number, since it uses as much as digits as its factorization.

20540261 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 419203 (or 419196 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 20.

The square root of 20540261 is about 4532.1364719081. The cubic root of 20540261 is about 273.8642346920.

Adding to 20540261 its reverse (16204502), we get a palindrome (36744763).

The spelling of 20540261 in words is "twenty million, five hundred forty thousand, two hundred sixty-one".