1644195836644 has 9 divisors (see below), whose sum is σ = 2877347202051. Its totient is φ = 822096636060.

The previous prime is 1644195836603. The next prime is 1644195836651. The reversal of 1644195836644 is 4466385914461.

The square root of 1644195836644 is 1282262.

It is a perfect power (a square), and thus also a powerful number.

It is a super-3 number, since 3×1644195836644³ (a number of 38 digits) contains 333 as substring.

It is a Duffinian number.

It is an unprimeable number.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 2243959 + ... + 2885089.

Almost surely, 2^{1644195836644} is an apocalyptic number.

1644195836644 is the 1282262-nd square number.

It is an amenable number.

1644195836644 is a deficient number, since it is larger than the sum of its proper divisors (1233151365407).

1644195836644 is an frugal number, since it uses more digits than its factorization.

1644195836644 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1282266 (or 641133 counting only the distinct ones).

The product of its digits is 59719680, while the sum is 61.

The spelling of 1644195836644 in words is "one trillion, six hundred forty-four billion, one hundred ninety-five million, eight hundred thirty-six thousand, six hundred forty-four".