1644867852 has 12 divisors (see below), whose sum is σ = 3838025016. Its totient is φ = 548289280.

The previous prime is 1644867821. The next prime is 1644867857. The reversal of 1644867852 is 2587684461.

It is a tau number, because it is divible by the number of its divisors (12).

It is a junction number, because it is equal to n+sod(n) for n = 1644867795 and 1644867804.

It is not an unprimeable number, because it can be changed into a prime (1644867857) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 68536149 + ... + 68536172.

It is an arithmetic number, because the mean of its divisors is an integer number (319835418).

Almost surely, 2^1644867852 is an apocalyptic number.

1644867852 is a gapful number since it is divisible by the number (12) formed by its first and last digit.

It is an amenable number.

1644867852 is an abundant number, since it is smaller than the sum of its proper divisors (2193157164).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1644867852 is a wasteful number, since it uses less digits than its factorization.

1644867852 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 137072328 (or 137072326 counting only the distinct ones).

The product of its digits is 2580480, while the sum is 51.

The square root of 1644867852 is about 40556.9704489869. The cubic root of 1644867852 is about 1180.4393298519.

The spelling of 1644867852 in words is "one billion, six hundred forty-four million, eight hundred sixty-seven thousand, eight hundred fifty-two".