644444840846026 has 32 divisors (see below), whose sum is σ = 1071837218134656. Its totient is φ = 288126416760000.

The previous prime is 644444840845991. The next prime is 644444840846029. The reversal of 644444840846026 is 620648048444446.

It is a super-2 number, since 2×644444840846026² (a number of 30 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (644444840846029) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 568580076 + ... + 569712376.

It is an arithmetic number, because the mean of its divisors is an integer number (33494913066708).

Almost surely, 2^{644444840846026} is an apocalyptic number.

644444840846026 is a deficient number, since it is larger than the sum of its proper divisors (427392377288630).

644444840846026 is a wasteful number, since it uses less digits than its factorization.

644444840846026 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1556478.

The product of its (nonzero) digits is 452984832, while the sum is 64.

The spelling of 644444840846026 in words is "six hundred forty-four trillion, four hundred forty-four billion, eight hundred forty million, eight hundred forty-six thousand, twenty-six".