812400209 has 2 divisors, whose sum is σ = 812400210. Its totient is φ = 812400208.

The previous prime is 812400191. The next prime is 812400263. The reversal of 812400209 is 902004218.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 809231809 + 3168400 = 28447^2 + 1780^2 .

It is a cyclic number.

It is not a de Polignac number, because 812400209 - 2¹⁶ = 812334673 is a prime.

It is a super-3 number, since 3×812400209³ (a number of 28 digits) contains 333 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (812400269) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 406200104 + 406200105.

It is an arithmetic number, because the mean of its divisors is an integer number (406200105).

Almost surely, 2^812400209 is an apocalyptic number.

It is an amenable number.

812400209 is a deficient number, since it is larger than the sum of its proper divisors (1).

812400209 is an equidigital number, since it uses as much as digits as its factorization.

812400209 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 26.

The square root of 812400209 is about 28502.6351237916. The cubic root of 812400209 is about 933.0895854842.

The spelling of 812400209 in words is "eight hundred twelve million, four hundred thousand, two hundred nine".