1643573856 has 96 divisors (see below), whose sum is σ = 4404153600. Its totient is φ = 536532480.

The previous prime is 1643573837. The next prime is 1643573861. The reversal of 1643573856 is 6583753461.

1643573856 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a tau number, because it is divible by the number of its divisors (96).

It is a hoax number, since the sum of its digits (48) coincides with the sum of the digits of its distinct prime factors.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2486166 + ... + 2486826.

It is an arithmetic number, because the mean of its divisors is an integer number (45876600).

Almost surely, 2^1643573856 is an apocalyptic number.

1643573856 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1643573856, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2202076800).

1643573856 is an abundant number, since it is smaller than the sum of its proper divisors (2760579744).

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

1643573856 is a wasteful number, since it uses less digits than its factorization.

1643573856 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1172 (or 1164 counting only the distinct ones).

The product of its digits is 1814400, while the sum is 48.

The square root of 1643573856 is about 40541.0144914998. The cubic root of 1643573856 is about 1180.1297032569.

The spelling of 1643573856 in words is "one billion, six hundred forty-three million, five hundred seventy-three thousand, eight hundred fifty-six".