1644653155 has 4 divisors (see below), whose sum is σ = 1973583792. Its totient is φ = 1315722520.

The previous prime is 1644653119. The next prime is 1644653239. The reversal of 1644653155 is 5513564461.

It is a happy number.

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

It is not a de Polignac number, because 1644653155 - 2⁹ = 1644652643 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian 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, 164465311 + ... + 164465320.

It is an arithmetic number, because the mean of its divisors is an integer number (493395948).

Almost surely, 2^1644653155 is an apocalyptic number.

1644653155 is a deficient number, since it is larger than the sum of its proper divisors (328930637).

1644653155 is an equidigital number, since it uses as much as digits as its factorization.

1644653155 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 328930636.

The product of its digits is 216000, while the sum is 40.

The square root of 1644653155 is about 40554.3235056387. The cubic root of 1644653155 is about 1180.3879685201.

The spelling of 1644653155 in words is "one billion, six hundred forty-four million, six hundred fifty-three thousand, one hundred fifty-five".