100165561 has 4 divisors (see below), whose sum is σ = 100188900. Its totient is φ = 100142224.

The previous prime is 100165523. The next prime is 100165567. The reversal of 100165561 is 165561001.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 21949225 + 78216336 = 4685^2 + 8844^2 .

It is a cyclic number.

It is not a de Polignac number, because 100165561 - 2⁹ = 100165049 is a prime.

It is a super-2 number, since 2×100165561² = 20066279220889442, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (100165567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3166 + ... + 14503.

It is an arithmetic number, because the mean of its divisors is an integer number (25047225).

Almost surely, 2^100165561 is an apocalyptic number.

It is an amenable number.

100165561 is a deficient number, since it is larger than the sum of its proper divisors (23339).

100165561 is an equidigital number, since it uses as much as digits as its factorization.

100165561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23338.

The product of its (nonzero) digits is 900, while the sum is 25.

The square root of 100165561 is about 10008.2746265278. The cubic root of 100165561 is about 464.4148974897.

The spelling of 100165561 in words is "one hundred million, one hundred sixty-five thousand, five hundred sixty-one".