6400655 has 4 divisors (see below), whose sum is σ = 7680792. Its totient is φ = 5120520.

The previous prime is 6400637. The next prime is 6400657. The reversal of 6400655 is 5560046.

It is a semiprime because it is the product of two primes.

It is not a de Polignac number, because 6400655 - 2⁶ = 6400591 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 (6400657) 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, 640061 + ... + 640070.

It is an arithmetic number, because the mean of its divisors is an integer number (1920198).

Almost surely, 2^6400655 is an apocalyptic number.

6400655 is a deficient number, since it is larger than the sum of its proper divisors (1280137).

6400655 is a wasteful number, since it uses less digits than its factorization.

6400655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1280136.

The product of its (nonzero) digits is 3600, while the sum is 26.

The square root of 6400655 is about 2529.9515805643. The cubic root of 6400655 is about 185.6698869632.

The spelling of 6400655 in words is "six million, four hundred thousand, six hundred fifty-five".