2640678686 has 4 divisors (see below), whose sum is σ = 3961018032. Its totient is φ = 1320339342.

The previous prime is 2640678659. The next prime is 2640678701. The reversal of 2640678686 is 6868760462.

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

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 660169670 + ... + 660169673.

It is an arithmetic number, because the mean of its divisors is an integer number (990254508).

Almost surely, 2^2640678686 is an apocalyptic number.

2640678686 is a deficient number, since it is larger than the sum of its proper divisors (1320339346).

2640678686 is a wasteful number, since it uses less digits than its factorization.

2640678686 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1320339345.

The product of its (nonzero) digits is 4644864, while the sum is 53.

The square root of 2640678686 is about 51387.5343444303. The cubic root of 2640678686 is about 1382.2030703875.

The spelling of 2640678686 in words is "two billion, six hundred forty million, six hundred seventy-eight thousand, six hundred eighty-six".