211321993 has 2 divisors, whose sum is σ = 211321994. Its totient is φ = 211321992.

The previous prime is 211321991. The next prime is 211322003. The reversal of 211321993 is 399123112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 195664144 + 15657849 = 13988^2 + 3957^2 .

It is a cyclic number.

It is not a de Polignac number, because 211321993 - 2¹ = 211321991 is a prime.

Together with 211321991, it forms a pair of twin primes.

It is not a weakly prime, because it can be changed into another prime (211321991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105660996 + 105660997.

It is an arithmetic number, because the mean of its divisors is an integer number (105660997).

Almost surely, 2^211321993 is an apocalyptic number.

It is an amenable number.

211321993 is a deficient number, since it is larger than the sum of its proper divisors (1).

211321993 is an equidigital number, since it uses as much as digits as its factorization.

211321993 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2916, while the sum is 31.

The square root of 211321993 is about 14536.9182772691. The cubic root of 211321993 is about 595.6368606369.

The spelling of 211321993 in words is "two hundred eleven million, three hundred twenty-one thousand, nine hundred ninety-three".