2640431 has 4 divisors (see below), whose sum is σ = 2711832. Its totient is φ = 2569032.

The previous prime is 2640409. The next prime is 2640497. The reversal of 2640431 is 1340462.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 1340462 = 2 ⋅670231.

It is a cyclic number.

It is not a de Polignac number, because 2640431 - 2⁶ = 2640367 is a prime.

It is a super-2 number, since 2×2640431² = 13943751731522, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2645431) 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, 35645 + ... + 35718.

It is an arithmetic number, because the mean of its divisors is an integer number (677958).

2^2640431 is an apocalyptic number.

2640431 is a deficient number, since it is larger than the sum of its proper divisors (71401).

2640431 is an equidigital number, since it uses as much as digits as its factorization.

2640431 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 71400.

The product of its (nonzero) digits is 576, while the sum is 20.

The square root of 2640431 is about 1624.9403065959. The cubic root of 2640431 is about 138.2159853839.

Adding to 2640431 its reverse (1340462), we get a palindrome (3980893).

The spelling of 2640431 in words is "two million, six hundred forty thousand, four hundred thirty-one".