2688239021 has 4 divisors (see below), whose sum is σ = 2895026652. Its totient is φ = 2481451392.

The previous prime is 2688238979. The next prime is 2688239039. The reversal of 2688239021 is 1209328862.

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

It can be written as a sum of positive squares in 2 ways, for example, as 728406121 + 1959832900 = 26989^2 + 44270^2 .

It is a cyclic number.

It is not a de Polignac number, because 2688239021 - 2¹⁸ = 2687976877 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 2688239021.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2688239221) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 103393796 + ... + 103393821.

It is an arithmetic number, because the mean of its divisors is an integer number (723756663).

Almost surely, 2^2688239021 is an apocalyptic number.

It is an amenable number.

2688239021 is a deficient number, since it is larger than the sum of its proper divisors (206787631).

2688239021 is a wasteful number, since it uses less digits than its factorization.

2688239021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206787630.

The product of its (nonzero) digits is 82944, while the sum is 41.

The square root of 2688239021 is about 51848.2306448349. The cubic root of 2688239021 is about 1390.4518692016.

The spelling of 2688239021 in words is "two billion, six hundred eighty-eight million, two hundred thirty-nine thousand, twenty-one".