1643654120 has 16 divisors (see below), whose sum is σ = 3698221860. Its totient is φ = 657461632.

The previous prime is 1643654119. The next prime is 1643654149. The reversal of 1643654120 is 214563461.

It can be written as a sum of positive squares in 2 ways, for example, as 1537110436 + 106543684 = 39206^2 + 10322^2 .

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, 20545637 + ... + 20545716.

Almost surely, 2^1643654120 is an apocalyptic number.

1643654120 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1643654120 is an abundant number, since it is smaller than the sum of its proper divisors (2054567740).

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

1643654120 is a wasteful number, since it uses less digits than its factorization.

1643654120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41091364 (or 41091360 counting only the distinct ones).

The product of its (nonzero) digits is 17280, while the sum is 32.

The square root of 1643654120 is about 40542.0043905084. The cubic root of 1643654120 is about 1180.1489135058.

The spelling of 1643654120 in words is "one billion, six hundred forty-three million, six hundred fifty-four thousand, one hundred twenty".