1644553445 has 4 divisors (see below), whose sum is σ = 1973464140. Its totient is φ = 1315642752.

The previous prime is 1644553381. The next prime is 1644553457. The reversal of 1644553445 is 5443554461.

1644553445 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 294946276 + 1349607169 = 17174^2 + 36737^2 .

It is a cyclic number.

It is not a de Polignac number, because 1644553445 - 2⁶ = 1644553381 is a prime.

It is a super-2 number, since 2×1644553445² = 5409112066922736050, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 164455340 + ... + 164455349.

It is an arithmetic number, because the mean of its divisors is an integer number (493366035).

Almost surely, 2^1644553445 is an apocalyptic number.

It is an amenable number.

1644553445 is a deficient number, since it is larger than the sum of its proper divisors (328910695).

1644553445 is an equidigital number, since it uses as much as digits as its factorization.

1644553445 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 328910694.

The product of its digits is 576000, while the sum is 41.

The square root of 1644553445 is about 40553.0941482891. The cubic root of 1644553445 is about 1180.3641136701.

The spelling of 1644553445 in words is "one billion, six hundred forty-four million, five hundred fifty-three thousand, four hundred forty-five".