216002121221 has 2 divisors, whose sum is σ = 216002121222. Its totient is φ = 216002121220.

The previous prime is 216002121199. The next prime is 216002121229. The reversal of 216002121221 is 122121200612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 182645116900 + 33357004321 = 427370^2 + 182639^2 .

It is a cyclic number.

It is not a de Polignac number, because 216002121221 - 2⁶ = 216002121157 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 216002121193 and 216002121202.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (216002121229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108001060610 + 108001060611.

It is an arithmetic number, because the mean of its divisors is an integer number (108001060611).

Almost surely, 2^216002121221 is an apocalyptic number.

It is an amenable number.

216002121221 is a deficient number, since it is larger than the sum of its proper divisors (1).

216002121221 is an equidigital number, since it uses as much as digits as its factorization.

216002121221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 192, while the sum is 20.

Adding to 216002121221 its reverse (122121200612), we get a palindrome (338123321833).

The spelling of 216002121221 in words is "two hundred sixteen billion, two million, one hundred twenty-one thousand, two hundred twenty-one".