644158590806 has 16 divisors (see below), whose sum is σ = 968582371344. Its totient is φ = 321297974784.

The previous prime is 644158590721. The next prime is 644158590809. The reversal of 644158590806 is 608095851446.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (644158590809) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8312270 + ... + 8389406.

It is an arithmetic number, because the mean of its divisors is an integer number (60536398209).

Almost surely, 2^644158590806 is an apocalyptic number.

644158590806 is a deficient number, since it is larger than the sum of its proper divisors (324423780538).

644158590806 is a wasteful number, since it uses less digits than its factorization.

644158590806 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 87215.

The product of its (nonzero) digits is 8294400, while the sum is 56.

The spelling of 644158590806 in words is "six hundred forty-four billion, one hundred fifty-eight million, five hundred ninety thousand, eight hundred six".