540639 has 24 divisors (see below), whose sum is σ = 878592. Its totient is φ = 317520.

The previous prime is 540629. The next prime is 540677. The reversal of 540639 is 936045.

It is a happy number.

It is not a de Polignac number, because 540639 - 2⁷ = 540511 is a prime.

540639 is a lucky number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 540639.

It is not an unprimeable number, because it can be changed into a prime (540619) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 4194 + ... + 4320.

It is an arithmetic number, because the mean of its divisors is an integer number (36608).

2⁵⁴⁰⁶³⁹ is an apocalyptic number.

540639 is a deficient number, since it is larger than the sum of its proper divisors (337953).

540639 is a wasteful number, since it uses less digits than its factorization.

540639 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 187 (or 184 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

The square root of 540639 is about 735.2815787166. The cubic root of 540639 is about 81.4646364448.

It can be divided in two parts, 5406 and 39, that added together give a palindrome (5445).

The spelling of 540639 in words is "five hundred forty thousand, six hundred thirty-nine".