2668639 has 2 divisors, whose sum is σ = 2668640. Its totient is φ = 2668638.

The previous prime is 2668637. The next prime is 2668663. The reversal of 2668639 is 9368662.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 2668639 - 2¹ = 2668637 is a prime.

It is a super-2 number, since 2×2668639² = 14243268224642, which contains 22 as substring.

Together with 2668637, it forms a pair of twin primes.

It is an Ulam number.

2668639 is a lucky number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2668637) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1334319 + 1334320.

It is an arithmetic number, because the mean of its divisors is an integer number (1334320).

2^2668639 is an apocalyptic number.

2668639 is a deficient number, since it is larger than the sum of its proper divisors (1).

2668639 is an equidigital number, since it uses as much as digits as its factorization.

2668639 is an evil number, because the sum of its binary digits is even.

The product of its digits is 93312, while the sum is 40.

The square root of 2668639 is about 1633.5969515153. The cubic root of 2668639 is about 138.7064349335.

The spelling of 2668639 in words is "two million, six hundred sixty-eight thousand, six hundred thirty-nine".