2540405 has 12 divisors (see below), whose sum is σ = 3546540. Its totient is φ = 1741824.

The previous prime is 2540393. The next prime is 2540407. The reversal of 2540405 is 5040452.

2540405 = 110² + 111² + ... + 207².

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 461041 + 2079364 = 679^2 + 1442^2 .

It is not a de Polignac number, because 2540405 - 2⁴ = 2540389 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2540407) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4940 + ... + 5429.

It is an arithmetic number, because the mean of its divisors is an integer number (295545).

2^2540405 is an apocalyptic number.

It is an amenable number.

2540405 is a deficient number, since it is larger than the sum of its proper divisors (1006135).

2540405 is a wasteful number, since it uses less digits than its factorization.

2540405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10388 (or 10381 counting only the distinct ones).

The product of its (nonzero) digits is 800, while the sum is 20.

The square root of 2540405 is about 1593.8647997870. The cubic root of 2540405 is about 136.4481503709.

Adding to 2540405 its reverse (5040452), we get a palindrome (7580857).

The spelling of 2540405 in words is "two million, five hundred forty thousand, four hundred five".