213205171221 has 32 divisors (see below), whose sum is σ = 363737932800. Its totient is φ = 120901500720.

The previous prime is 213205171147. The next prime is 213205171229. The reversal of 213205171221 is 122171502312.

It is a happy number.

213205171221 is a `hidden beast` number, since 2 + 1 + 3 + 20 + 517 + 122 + 1 = 666.

It is not a de Polignac number, because 213205171221 - 2⁷ = 213205171093 is a prime.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (213205171229) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 4280851 + ... + 4330368.

It is an arithmetic number, because the mean of its divisors is an integer number (11366810400).

Almost surely, 2^213205171221 is an apocalyptic number.

213205171221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

213205171221 is a deficient number, since it is larger than the sum of its proper divisors (150532761579).

213205171221 is a wasteful number, since it uses less digits than its factorization.

213205171221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8611366 (or 8611360 counting only the distinct ones).

The product of its (nonzero) digits is 1680, while the sum is 27.

Adding to 213205171221 its reverse (122171502312), we get a palindrome (335376673533).

The spelling of 213205171221 in words is "two hundred thirteen billion, two hundred five million, one hundred seventy-one thousand, two hundred twenty-one".