6491640771 has 96 divisors (see below), whose sum is σ = 11899630080. Its totient is φ = 3312576000.

The previous prime is 6491640769. The next prime is 6491640809. The reversal of 6491640771 is 1770461946.

It is not a de Polignac number, because 6491640771 - 2¹ = 6491640769 is a prime.

It is not an unprimeable number, because it can be changed into a prime (6491640751) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 11408575 + ... + 11409143.

It is an arithmetic number, because the mean of its divisors is an integer number (123954480).

Almost surely, 2^6491640771 is an apocalyptic number.

6491640771 is a deficient number, since it is larger than the sum of its proper divisors (5407989309).

6491640771 is a wasteful number, since it uses less digits than its factorization.

6491640771 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 857 (or 854 counting only the distinct ones).

The product of its (nonzero) digits is 254016, while the sum is 45.

The square root of 6491640771 is about 80570.7190671648. The cubic root of 6491640771 is about 1865.4552117361.

The spelling of 6491640771 in words is "six billion, four hundred ninety-one million, six hundred forty thousand, seven hundred seventy-one".