100115561 has 8 divisors (see below), whose sum is σ = 123219264. Its totient is φ = 79212240.

The previous prime is 100115551. The next prime is 100115581. The reversal of 100115561 is 165511001.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 100115561 - 2¹⁴ = 100099177 is a prime.

It is not an unprimeable number, because it can be changed into a prime (100115501) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 549995 + ... + 550176.

It is an arithmetic number, because the mean of its divisors is an integer number (15402408).

Almost surely, 2^100115561 is an apocalyptic number.

It is an amenable number.

100115561 is a deficient number, since it is larger than the sum of its proper divisors (23103703).

100115561 is a wasteful number, since it uses less digits than its factorization.

100115561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1100191.

The product of its (nonzero) digits is 150, while the sum is 20.

The square root of 100115561 is about 10005.7763816707. The cubic root of 100115561 is about 464.3376100819.

Adding to 100115561 its reverse (165511001), we get a palindrome (265626562).

The spelling of 100115561 in words is "one hundred million, one hundred fifteen thousand, five hundred sixty-one".