216252165561 has 4 divisors (see below), whose sum is σ = 288336220752. Its totient is φ = 144168110372.

The previous prime is 216252165533. The next prime is 216252165589. The reversal of 216252165561 is 165561252612.

216252165561 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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 an interprime number because it is at equal distance from previous prime (216252165533) and next prime (216252165589).

It is a cyclic number.

It is not a de Polignac number, because 216252165561 - 2¹⁵ = 216252132793 is a prime.

It is not an unprimeable number, because it can be changed into a prime (216252165511) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 36042027591 + ... + 36042027596.

It is an arithmetic number, because the mean of its divisors is an integer number (72084055188).

Almost surely, 2^216252165561 is an apocalyptic number.

It is an amenable number.

216252165561 is a deficient number, since it is larger than the sum of its proper divisors (72084055191).

216252165561 is an equidigital number, since it uses as much as digits as its factorization.

216252165561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 72084055190.

The product of its digits is 216000, while the sum is 42.

It can be divided in two parts, 21625 and 2165561, that added together give a triangular number (2187186 = T₂₀₉₁).

The spelling of 216252165561 in words is "two hundred sixteen billion, two hundred fifty-two million, one hundred sixty-five thousand, five hundred sixty-one".