1644189216 has 48 divisors (see below), whose sum is σ = 4421275488. Its totient is φ = 534694400.

The previous prime is 1644189199. The next prime is 1644189227. The reversal of 1644189216 is 6129814461.

It is a tau number, because it is divible by the number of its divisors (48).

It is a super-3 number, since 3×1644189216³ (a number of 29 digits) contains 333 as substring.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 204930 + ... + 212801.

It is an arithmetic number, because the mean of its divisors is an integer number (92109906).

Almost surely, 2^1644189216 is an apocalyptic number.

1644189216 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

1644189216 is an abundant number, since it is smaller than the sum of its proper divisors (2777086272).

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

1644189216 is a wasteful number, since it uses less digits than its factorization.

1644189216 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 417785 (or 417777 counting only the distinct ones).

The product of its digits is 82944, while the sum is 42.

The square root of 1644189216 is about 40548.6031325371. The cubic root of 1644189216 is about 1180.2769664904.

The spelling of 1644189216 in words is "one billion, six hundred forty-four million, one hundred eighty-nine thousand, two hundred sixteen".