1644654145 has 4 divisors (see below), whose sum is σ = 1973584980. Its totient is φ = 1315723312.

The previous prime is 1644654139. The next prime is 1644654149. The reversal of 1644654145 is 5414564461.

It is a happy number.

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 391564944 + 1253089201 = 19788^2 + 35399^2 .

It is a cyclic number.

It is not a de Polignac number, because 1644654145 - 2⁷ = 1644654017 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1644654098 and 1644654107.

It is not an unprimeable number, because it can be changed into a prime (1644654149) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 164465410 + ... + 164465419.

It is an arithmetic number, because the mean of its divisors is an integer number (493396245).

Almost surely, 2^1644654145 is an apocalyptic number.

It is an amenable number.

1644654145 is a deficient number, since it is larger than the sum of its proper divisors (328930835).

1644654145 is an equidigital number, since it uses as much as digits as its factorization.

1644654145 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 328930834.

The product of its digits is 230400, while the sum is 40.

The square root of 1644654145 is about 40554.3357114871. The cubic root of 1644654145 is about 1180.3882053652.

The spelling of 1644654145 in words is "one billion, six hundred forty-four million, six hundred fifty-four thousand, one hundred forty-five".