1644553655 has 4 divisors (see below), whose sum is σ = 1973464392. Its totient is φ = 1315642920.

The previous prime is 1644553639. The next prime is 1644553661. The reversal of 1644553655 is 5563554461.

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

It is not a de Polignac number, because 1644553655 - 2⁴ = 1644553639 is a prime.

It is a Duffinian number.

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, 164455361 + ... + 164455370.

It is an arithmetic number, because the mean of its divisors is an integer number (493366098).

Almost surely, 2^1644553655 is an apocalyptic number.

1644553655 is a deficient number, since it is larger than the sum of its proper divisors (328910737).

1644553655 is an equidigital number, since it uses as much as digits as its factorization.

1644553655 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 328910736.

The product of its digits is 1080000, while the sum is 44.

The square root of 1644553655 is about 40553.0967374873. The cubic root of 1644553655 is about 1180.3641639120.

The spelling of 1644553655 in words is "one billion, six hundred forty-four million, five hundred fifty-three thousand, six hundred fifty-five".