6640752391 has 24 divisors (see below), whose sum is σ = 8361571680. Its totient is φ = 5227451712.

The previous prime is 6640752361. The next prime is 6640752397. The reversal of 6640752391 is 1932570466.

6640752391 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 6640752391 - 2⁵ = 6640752359 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6640752397) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 99030 + ... + 151948.

It is an arithmetic number, because the mean of its divisors is an integer number (348398820).

Almost surely, 2^6640752391 is an apocalyptic number.

6640752391 is a deficient number, since it is larger than the sum of its proper divisors (1720819289).

6640752391 is a wasteful number, since it uses less digits than its factorization.

6640752391 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53143 (or 53136 counting only the distinct ones).

The product of its (nonzero) digits is 272160, while the sum is 43.

The square root of 6640752391 is about 81490.8116967797. The cubic root of 6640752391 is about 1879.6302644520.

The spelling of 6640752391 in words is "six billion, six hundred forty million, seven hundred fifty-two thousand, three hundred ninety-one".