212491817 has 2 divisors, whose sum is σ = 212491818. Its totient is φ = 212491816.

The previous prime is 212491813. The next prime is 212491819. The reversal of 212491817 is 718194212.

212491817 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 212459776 + 32041 = 14576^2 + 179^2 .

It is a cyclic number.

It is not a de Polignac number, because 212491817 - 2² = 212491813 is a prime.

It is a super-2 number, since 2×212491817² = 90305544583922978, which contains 22 as substring.

Together with 212491819, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (212491813) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106245908 + 106245909.

It is an arithmetic number, because the mean of its divisors is an integer number (106245909).

Almost surely, 2^212491817 is an apocalyptic number.

It is an amenable number.

212491817 is a deficient number, since it is larger than the sum of its proper divisors (1).

212491817 is an equidigital number, since it uses as much as digits as its factorization.

212491817 is an evil number, because the sum of its binary digits is even.

The product of its digits is 8064, while the sum is 35.

The square root of 212491817 is about 14577.0990598267. The cubic root of 212491817 is about 596.7339360434.

The spelling of 212491817 in words is "two hundred twelve million, four hundred ninety-one thousand, eight hundred seventeen".