6400257666 has 16 divisors (see below), whose sum is σ = 13964198688. Its totient is φ = 1939472000.

The previous prime is 6400257659. The next prime is 6400257671. The reversal of 6400257666 is 6667520046.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 48486735 + ... + 48486866.

It is an arithmetic number, because the mean of its divisors is an integer number (872762418).

Almost surely, 2^6400257666 is an apocalyptic number.

6400257666 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

6400257666 is an abundant number, since it is smaller than the sum of its proper divisors (7563941022).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

6400257666 is a wasteful number, since it uses less digits than its factorization.

6400257666 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 96973617.

The product of its (nonzero) digits is 362880, while the sum is 42.

The square root of 6400257666 is about 80001.6103962914. The cubic root of 6400257666 is about 1856.6604493530.

The spelling of 6400257666 in words is "six billion, four hundred million, two hundred fifty-seven thousand, six hundred sixty-six".