216921113 has 2 divisors, whose sum is σ = 216921114. Its totient is φ = 216921112.

The previous prime is 216921109. The next prime is 216921127. The reversal of 216921113 is 311129612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 186923584 + 29997529 = 13672^2 + 5477^2 .

It is a cyclic number.

It is not a de Polignac number, because 216921113 - 2² = 216921109 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (216921163) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108460556 + 108460557.

It is an arithmetic number, because the mean of its divisors is an integer number (108460557).

Almost surely, 2^216921113 is an apocalyptic number.

It is an amenable number.

216921113 is a deficient number, since it is larger than the sum of its proper divisors (1).

216921113 is an equidigital number, since it uses as much as digits as its factorization.

216921113 is an evil number, because the sum of its binary digits is even.

The product of its digits is 648, while the sum is 26.

The square root of 216921113 is about 14728.2420200104. The cubic root of 216921113 is about 600.8516729241.

The spelling of 216921113 in words is "two hundred sixteen million, nine hundred twenty-one thousand, one hundred thirteen".