216453727005661 has 4 divisors (see below), whose sum is σ = 216472087669500. Its totient is φ = 216435366341824.

The previous prime is 216453727005623. The next prime is 216453727005667. The reversal of 216453727005661 is 166500727354612.

It is a happy number.

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 4264249780036 + 212189477225625 = 2065006^2 + 14566725^2 .

It is a cyclic number.

It is not a de Polignac number, because 216453727005661 - 2²⁹ = 216453190134749 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216453727005667) 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, 9180314236 + ... + 9180337813.

It is an arithmetic number, because the mean of its divisors is an integer number (54118021917375).

Almost surely, 2^{216453727005661} is an apocalyptic number.

It is an amenable number.

216453727005661 is a deficient number, since it is larger than the sum of its proper divisors (18360663839).

216453727005661 is a wasteful number, since it uses less digits than its factorization.

216453727005661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18360663838.

The product of its (nonzero) digits is 12700800, while the sum is 55.

The spelling of 216453727005661 in words is "two hundred sixteen trillion, four hundred fifty-three billion, seven hundred twenty-seven million, five thousand, six hundred sixty-one".