2643691 has 2 divisors, whose sum is σ = 2643692. Its totient is φ = 2643690.

The previous prime is 2643677. The next prime is 2643709. The reversal of 2643691 is 1963462.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2643691 - 2⁵ = 2643659 is a prime.

It is not a weakly prime, because it can be changed into another prime (2643661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1321845 + 1321846.

It is an arithmetic number, because the mean of its divisors is an integer number (1321846).

2^2643691 is an apocalyptic number.

2643691 is a deficient number, since it is larger than the sum of its proper divisors (1).

2643691 is an equidigital number, since it uses as much as digits as its factorization.

2643691 is an evil number, because the sum of its binary digits is even.

The product of its digits is 7776, while the sum is 31.

The square root of 2643691 is about 1625.9431109359. The cubic root of 2643691 is about 138.2728446368.

The spelling of 2643691 in words is "two million, six hundred forty-three thousand, six hundred ninety-one".