1643665164 has 12 divisors (see below), whose sum is σ = 3835218744. Its totient is φ = 547888384.

The previous prime is 1643665147. The next prime is 1643665187. The reversal of 1643665164 is 4615663461.

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

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, 68486037 + ... + 68486060.

It is an arithmetic number, because the mean of its divisors is an integer number (319601562).

Almost surely, 2^1643665164 is an apocalyptic number.

It is an amenable number.

1643665164 is an abundant number, since it is smaller than the sum of its proper divisors (2191553580).

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

1643665164 is a wasteful number, since it uses less digits than its factorization.

1643665164 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 136972104 (or 136972102 counting only the distinct ones).

The product of its digits is 311040, while the sum is 42.

The square root of 1643665164 is about 40542.1405946948. The cubic root of 1643665164 is about 1180.1515567090.

The spelling of 1643665164 in words is "one billion, six hundred forty-three million, six hundred sixty-five thousand, one hundred sixty-four".