6442540655 has 4 divisors (see below), whose sum is σ = 7731048792. Its totient is φ = 5154032520.

The previous prime is 6442540627. The next prime is 6442540667. The reversal of 6442540655 is 5560452446.

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

It is not a de Polignac number, because 6442540655 - 2⁸ = 6442540399 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 644254061 + ... + 644254070.

It is an arithmetic number, because the mean of its divisors is an integer number (1932762198).

Almost surely, 2^6442540655 is an apocalyptic number.

6442540655 is a deficient number, since it is larger than the sum of its proper divisors (1288508137).

6442540655 is a wasteful number, since it uses less digits than its factorization.

6442540655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1288508136.

The product of its (nonzero) digits is 576000, while the sum is 41.

The square root of 6442540655 is about 80265.4387329939. The cubic root of 6442540655 is about 1860.7401239029.

The spelling of 6442540655 in words is "six billion, four hundred forty-two million, five hundred forty thousand, six hundred fifty-five".