212123491 has 2 divisors, whose sum is σ = 212123492. Its totient is φ = 212123490.

The previous prime is 212123419. The next prime is 212123507. The reversal of 212123491 is 194321212.

Together with previous prime (212123419) it forms an Ormiston pair, because they use the same digits, order apart.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-212123491 is a prime.

It is not a weakly prime, because it can be changed into another prime (212126491) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 106061745 + 106061746.

It is an arithmetic number, because the mean of its divisors is an integer number (106061746).

Almost surely, 2^212123491 is an apocalyptic number.

212123491 is a deficient number, since it is larger than the sum of its proper divisors (1).

212123491 is an equidigital number, since it uses as much as digits as its factorization.

212123491 is an evil number, because the sum of its binary digits is even.

The product of its digits is 864, while the sum is 25.

The square root of 212123491 is about 14564.4598595348. The cubic root of 212123491 is about 596.3889506177.

The spelling of 212123491 in words is "two hundred twelve million, one hundred twenty-three thousand, four hundred ninety-one".