161099138521 has 32 divisors (see below), whose sum is σ = 177400855296. Its totient is φ = 145673472000.

The previous prime is 161099138491. The next prime is 161099138531. The reversal of 161099138521 is 125831990161.

It is a cyclic number.

It is not a de Polignac number, because 161099138521 - 2⁷ = 161099138393 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (161099138531) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 67944466 + ... + 67946836.

It is an arithmetic number, because the mean of its divisors is an integer number (5543776728).

Almost surely, 2^161099138521 is an apocalyptic number.

It is an amenable number.

161099138521 is a deficient number, since it is larger than the sum of its proper divisors (16301716775).

161099138521 is a wasteful number, since it uses less digits than its factorization.

161099138521 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3873.

The product of its (nonzero) digits is 116640, while the sum is 46.

The spelling of 161099138521 in words is "one hundred sixty-one billion, ninety-nine million, one hundred thirty-eight thousand, five hundred twenty-one".