6640501557 has 12 divisors (see below), whose sum is σ = 9255698144. Its totient is φ = 4234521720.

The previous prime is 6640501547. The next prime is 6640501559. The reversal of 6640501557 is 7551050466.

6640501557 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 6640501557 - 2¹⁹ = 6639977269 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6640501559) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2090569 + ... + 2093742.

Almost surely, 2^6640501557 is an apocalyptic number.

It is an amenable number.

6640501557 is a deficient number, since it is larger than the sum of its proper divisors (2615196587).

6640501557 is a wasteful number, since it uses less digits than its factorization.

6640501557 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4184360 (or 4184337 counting only the distinct ones).

The product of its (nonzero) digits is 126000, while the sum is 39.

The square root of 6640501557 is about 81489.2726498402. The cubic root of 6640501557 is about 1879.6065984031.

The spelling of 6640501557 in words is "six billion, six hundred forty million, five hundred one thousand, five hundred fifty-seven".