1643500161 has 12 divisors (see below), whose sum is σ = 2418736788. Its totient is φ = 1074993504.

The previous prime is 1643500153. The next prime is 1643500163. The reversal of 1643500161 is 1610053461.

1643500161 is a `hidden beast` number, since 1 + 643 + 5 + 0 + 0 + 16 + 1 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 397763136 + 1245737025 = 19944^2 + 35295^2 .

It is not a de Polignac number, because 1643500161 - 2³ = 1643500153 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1643500163) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1722270 + ... + 1723223.

It is an arithmetic number, because the mean of its divisors is an integer number (201561399).

Almost surely, 2^1643500161 is an apocalyptic number.

It is an amenable number.

1643500161 is a deficient number, since it is larger than the sum of its proper divisors (775236627).

1643500161 is a wasteful number, since it uses less digits than its factorization.

1643500161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3445552 (or 3445549 counting only the distinct ones).

The product of its (nonzero) digits is 2160, while the sum is 27.

The square root of 1643500161 is about 40540.1055869370. The cubic root of 1643500161 is about 1180.1120646705.

The spelling of 1643500161 in words is "one billion, six hundred forty-three million, five hundred thousand, one hundred sixty-one".