100161561 has 4 divisors (see below), whose sum is σ = 133548752. Its totient is φ = 66774372.

The previous prime is 100161547. The next prime is 100161587. The reversal of 100161561 is 165161001.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 100161561 - 2⁶ = 100161497 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (100161541) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16693591 + ... + 16693596.

It is an arithmetic number, because the mean of its divisors is an integer number (33387188).

Almost surely, 2^100161561 is an apocalyptic number.

It is an amenable number.

100161561 is a deficient number, since it is larger than the sum of its proper divisors (33387191).

100161561 is an equidigital number, since it uses as much as digits as its factorization.

100161561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33387190.

The product of its (nonzero) digits is 180, while the sum is 21.

The square root of 100161561 is about 10008.0747898884. The cubic root of 100161561 is about 464.4087154437.

The spelling of 100161561 in words is "one hundred million, one hundred sixty-one thousand, five hundred sixty-one".