101556561 has 4 divisors (see below), whose sum is σ = 135408752. Its totient is φ = 67704372.

The previous prime is 101556551. The next prime is 101556599. The reversal of 101556561 is 165655101.

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, and also an emirpimes, since its reverse is a distinct semiprime: 165655101 = 3 ⋅55218367.

It is not a de Polignac number, because 101556561 - 2⁵ = 101556529 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (101556551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 16926091 + ... + 16926096.

It is an arithmetic number, because the mean of its divisors is an integer number (33852188).

Almost surely, 2^101556561 is an apocalyptic number.

It is an amenable number.

101556561 is a deficient number, since it is larger than the sum of its proper divisors (33852191).

101556561 is an equidigital number, since it uses as much as digits as its factorization.

101556561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 33852190.

The product of its (nonzero) digits is 4500, while the sum is 30.

The square root of 101556561 is about 10077.5275241500. The cubic root of 101556561 is about 466.5548001136.

The spelling of 101556561 in words is "one hundred one million, five hundred fifty-six thousand, five hundred sixty-one".