2387664721 has 4 divisors (see below), whose sum is σ = 2571331252. Its totient is φ = 2203998192.

The previous prime is 2387664703. The next prime is 2387664757. The reversal of 2387664721 is 1274667832.

2387664721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 586850625 + 1800814096 = 24225^2 + 42436^2 .

It is a cyclic number.

It is not a de Polignac number, because 2387664721 - 2²⁵ = 2354110289 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (2387664701) 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, 91833246 + ... + 91833271.

It is an arithmetic number, because the mean of its divisors is an integer number (642832813).

Almost surely, 2^2387664721 is an apocalyptic number.

It is an amenable number.

2387664721 is a deficient number, since it is larger than the sum of its proper divisors (183666531).

2387664721 is a wasteful number, since it uses less digits than its factorization.

2387664721 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 183666530.

The product of its digits is 677376, while the sum is 46.

The square root of 2387664721 is about 48863.7362570649. The cubic root of 2387664721 is about 1336.5681696053.

The spelling of 2387664721 in words is "two billion, three hundred eighty-seven million, six hundred sixty-four thousand, seven hundred twenty-one".