2540645 has 4 divisors (see below), whose sum is σ = 3048780. Its totient is φ = 2032512.

The previous prime is 2540641. The next prime is 2540663. The reversal of 2540645 is 5460452.

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 329476 + 2211169 = 574^2 + 1487^2 .

It is a cyclic number.

It is not a de Polignac number, because 2540645 - 2² = 2540641 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2540641) 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, 254060 + ... + 254069.

It is an arithmetic number, because the mean of its divisors is an integer number (762195).

2^2540645 is an apocalyptic number.

It is an amenable number.

2540645 is a deficient number, since it is larger than the sum of its proper divisors (508135).

2540645 is an equidigital number, since it uses as much as digits as its factorization.

2540645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 508134.

The product of its (nonzero) digits is 4800, while the sum is 26.

The square root of 2540645 is about 1593.9400867034. The cubic root of 2540645 is about 136.4524471300.

The spelling of 2540645 in words is "two million, five hundred forty thousand, six hundred forty-five".