3138640 has 20 divisors (see below), whose sum is σ = 7297524. Its totient is φ = 1255424.

The previous prime is 3138637. The next prime is 3138647. The reversal of 3138640 is 468313.

3138640 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 501264 + 2637376 = 708^2 + 1624^2 .

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

It is a super-2 number, since 2×3138640² = 19702122099200, which contains 22 as substring.

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (3138647) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19537 + ... + 19696.

Almost surely, 2^3138640 is an apocalyptic number.

It is an amenable number.

3138640 is an abundant number, since it is smaller than the sum of its proper divisors (4158884).

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

3138640 is a wasteful number, since it uses less digits than its factorization.

3138640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 39246 (or 39240 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 25.

The square root of 3138640 is about 1771.6207269052. The cubic root of 3138640 is about 146.4132907201.

The spelling of 3138640 in words is "three million, one hundred thirty-eight thousand, six hundred forty".