6440731655 has 8 divisors (see below), whose sum is σ = 7995391200. Its totient is φ = 4974909856.

The previous prime is 6440731643. The next prime is 6440731669. The reversal of 6440731655 is 5561370446.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 6440731655 - 2²² = 6436537351 is a prime.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 22209275 + ... + 22209564.

It is an arithmetic number, because the mean of its divisors is an integer number (999423900).

Almost surely, 2^6440731655 is an apocalyptic number.

6440731655 is a deficient number, since it is larger than the sum of its proper divisors (1554659545).

6440731655 is a wasteful number, since it uses less digits than its factorization.

6440731655 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44418873.

The product of its (nonzero) digits is 302400, while the sum is 41.

The square root of 6440731655 is about 80254.1690817368. The cubic root of 6440731655 is about 1860.5659486219.

The spelling of 6440731655 in words is "six billion, four hundred forty million, seven hundred thirty-one thousand, six hundred fifty-five".