216165692221 has 4 divisors (see below), whose sum is σ = 216168588000. Its totient is φ = 216162796444.

The previous prime is 216165692219. The next prime is 216165692293. The reversal of 216165692221 is 122296561612.

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 a cyclic number.

It is not a de Polignac number, because 216165692221 - 2¹ = 216165692219 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 (216165692321) 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, 1332871 + ... + 1486228.

It is an arithmetic number, because the mean of its divisors is an integer number (54042147000).

Almost surely, 2^216165692221 is an apocalyptic number.

It is an amenable number.

216165692221 is a deficient number, since it is larger than the sum of its proper divisors (2895779).

216165692221 is an equidigital number, since it uses as much as digits as its factorization.

216165692221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2895778.

The product of its digits is 155520, while the sum is 43.

The spelling of 216165692221 in words is "two hundred sixteen billion, one hundred sixty-five million, six hundred ninety-two thousand, two hundred twenty-one".