213231211209 has 20 divisors (see below), whose sum is σ = 326299618260. Its totient is φ = 138686964480.

The previous prime is 213231211201. The next prime is 213231211241. The reversal of 213231211209 is 902112132312.

213231211209 is a `hidden beast` number, since 2 + 13 + 231 + 211 + 209 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 19543201209 + 193688010000 = 139797^2 + 440100^2 .

It is not a de Polignac number, because 213231211209 - 2³ = 213231211201 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (213231211201) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 32100144 + ... + 32106785.

It is an arithmetic number, because the mean of its divisors is an integer number (16314980913).

Almost surely, 2^213231211209 is an apocalyptic number.

It is an amenable number.

213231211209 is a deficient number, since it is larger than the sum of its proper divisors (113068407051).

213231211209 is an equidigital number, since it uses as much as digits as its factorization.

213231211209 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 64206982 (or 64206973 counting only the distinct ones).

The product of its (nonzero) digits is 1296, while the sum is 27.

The spelling of 213231211209 in words is "two hundred thirteen billion, two hundred thirty-one million, two hundred eleven thousand, two hundred nine".