2639440 has 20 divisors (see below), whose sum is σ = 6136884. Its totient is φ = 1055744.

The previous prime is 2639431. The next prime is 2639447. The reversal of 2639440 is 449362.

It can be written as a sum of positive squares in 2 ways, for example, as 484416 + 2155024 = 696^2 + 1468^2 .

It is a tau number, because it is divible by the number of its divisors (20).

It is a junction number, because it is equal to n+sod(n) for n = 2639399 and 2639408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2639447) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16417 + ... + 16576.

2^2639440 is an apocalyptic number.

2639440 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

2639440 is an abundant number, since it is smaller than the sum of its proper divisors (3497444).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

2639440 is a wasteful number, since it uses less digits than its factorization.

2639440 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33006 (or 33000 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 28.

The square root of 2639440 is about 1624.6353437002. The cubic root of 2639440 is about 138.1986915935.

The spelling of 2639440 in words is "two million, six hundred thirty-nine thousand, four hundred forty".