644400662006 has 16 divisors (see below), whose sum is σ = 970212902400. Its totient is φ = 320998433448.

The previous prime is 644400661991. The next prime is 644400662027. The reversal of 644400662006 is 600266004446.

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, 105155 + ... + 1140113.

It is an arithmetic number, because the mean of its divisors is an integer number (60638306400).

Almost surely, 2^644400662006 is an apocalyptic number.

644400662006 is a deficient number, since it is larger than the sum of its proper divisors (325812240394).

644400662006 is a wasteful number, since it uses less digits than its factorization.

644400662006 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1036123.

The product of its (nonzero) digits is 165888, while the sum is 38.

The spelling of 644400662006 in words is "six hundred forty-four billion, four hundred million, six hundred sixty-two thousand, six".