2640866 has 4 divisors (see below), whose sum is σ = 3961302. Its totient is φ = 1320432.

The previous prime is 2640863. The next prime is 2640871. The reversal of 2640866 is 6680462.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in only one way, i.e., 2627641 + 13225 = 1621^2 + 115^2 .

It is not an unprimeable number, because it can be changed into a prime (2640863) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660215 + ... + 660218.

2^2640866 is an apocalyptic number.

2640866 is a deficient number, since it is larger than the sum of its proper divisors (1320436).

2640866 is a wasteful number, since it uses less digits than its factorization.

2640866 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1320435.

The product of its (nonzero) digits is 13824, while the sum is 32.

The square root of 2640866 is about 1625.0741521543. The cubic root of 2640866 is about 138.2235751363.

The spelling of 2640866 in words is "two million, six hundred forty thousand, eight hundred sixty-six".