2640731 has 4 divisors (see below), whose sum is σ = 2644200. Its totient is φ = 2637264.

The previous prime is 2640721. The next prime is 2640739. The reversal of 2640731 is 1370462.

2640731 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1370462 = 2 ⋅685231.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-2640731 is a prime.

It is a super-2 number, since 2×2640731² = 13946920428722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 2640697 and 2640706.

It is not an unprimeable number, because it can be changed into a prime (2640739) 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, 41 + ... + 2298.

It is an arithmetic number, because the mean of its divisors is an integer number (661050).

2^2640731 is an apocalyptic number.

2640731 is a deficient number, since it is larger than the sum of its proper divisors (3469).

2640731 is a wasteful number, since it uses less digits than its factorization.

2640731 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3468.

The product of its (nonzero) digits is 1008, while the sum is 23.

The square root of 2640731 is about 1625.0326150573. The cubic root of 2640731 is about 138.2212197851.

The spelling of 2640731 in words is "two million, six hundred forty thousand, seven hundred thirty-one".