2640643 has 2 divisors, whose sum is σ = 2640644. Its totient is φ = 2640642.

The previous prime is 2640581. The next prime is 2640683. The reversal of 2640643 is 3460462.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2640643 - 2¹⁷ = 2509571 is a prime.

It is not a weakly prime, because it can be changed into another prime (2640683) by changing a digit.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1320321 + 1320322.

It is an arithmetic number, because the mean of its divisors is an integer number (1320322).

2^2640643 is an apocalyptic number.

2640643 is a deficient number, since it is larger than the sum of its proper divisors (1).

2640643 is an equidigital number, since it uses as much as digits as its factorization.

2640643 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3456, while the sum is 25.

The square root of 2640643 is about 1625.0055384521. The cubic root of 2640643 is about 138.2196844018.

The spelling of 2640643 in words is "two million, six hundred forty thousand, six hundred forty-three".