213110921 has 2 divisors, whose sum is σ = 213110922. Its totient is φ = 213110920.

The previous prime is 213110903. The next prime is 213110923. The reversal of 213110921 is 129011312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 205520896 + 7590025 = 14336^2 + 2755^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-213110921 is a prime.

It is a Sophie Germain prime.

Together with 213110923, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 213110893 and 213110902.

It is not a weakly prime, because it can be changed into another prime (213110923) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106555460 + 106555461.

It is an arithmetic number, because the mean of its divisors is an integer number (106555461).

Almost surely, 2^213110921 is an apocalyptic number.

It is an amenable number.

213110921 is a deficient number, since it is larger than the sum of its proper divisors (1).

213110921 is an equidigital number, since it uses as much as digits as its factorization.

213110921 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108, while the sum is 20.

The square root of 213110921 is about 14598.3191155694. The cubic root of 213110921 is about 597.3129107355.

The spelling of 213110921 in words is "two hundred thirteen million, one hundred ten thousand, nine hundred twenty-one".