100541561 has 4 divisors (see below), whose sum is σ = 101537124. Its totient is φ = 99546000.

The previous prime is 100541549. The next prime is 100541563. The reversal of 100541561 is 165145001.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 165145001 = 7 ⋅23592143.

It can be written as a sum of positive squares in 2 ways, for example, as 40386025 + 60155536 = 6355^2 + 7756^2 .

It is a cyclic number.

It is not a de Polignac number, because 100541561 - 2¹⁰ = 100540537 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (100541563) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 497630 + ... + 497831.

It is an arithmetic number, because the mean of its divisors is an integer number (25384281).

Almost surely, 2^100541561 is an apocalyptic number.

It is an amenable number.

100541561 is a deficient number, since it is larger than the sum of its proper divisors (995563).

100541561 is an equidigital number, since it uses as much as digits as its factorization.

100541561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 995562.

The product of its (nonzero) digits is 600, while the sum is 23.

The square root of 100541561 is about 10027.0414878966. The cubic root of 100541561 is about 464.9952764772.

Adding to 100541561 its reverse (165145001), we get a palindrome (265686562).

The spelling of 100541561 in words is "one hundred million, five hundred forty-one thousand, five hundred sixty-one".