216652321661 has 8 divisors (see below), whose sum is σ = 225007880760. Its totient is φ = 208428346368.

The previous prime is 216652321651. The next prime is 216652321673. The reversal of 216652321661 is 166123256612.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 79978668025 + 136673653636 = 282805^2 + 369694^2 .

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 216652321661 - 2³⁰ = 215578579837 is a prime.

It is a super-2 number, since 2×216652321661² (a number of 23 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (216652321651) 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, 32892596 + ... + 32899181.

It is an arithmetic number, because the mean of its divisors is an integer number (28125985095).

Almost surely, 2^216652321661 is an apocalyptic number.

It is an amenable number.

216652321661 is a deficient number, since it is larger than the sum of its proper divisors (8355559099).

216652321661 is an equidigital number, since it uses as much as digits as its factorization.

216652321661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65791903.

The product of its digits is 155520, while the sum is 41.

The spelling of 216652321661 in words is "two hundred sixteen billion, six hundred fifty-two million, three hundred twenty-one thousand, six hundred sixty-one".