1212316221 has 4 divisors (see below), whose sum is σ = 1616421632. Its totient is φ = 808210812.

The previous prime is 1212316213. The next prime is 1212316229. The reversal of 1212316221 is 1226132121.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is an interprime number because it is at equal distance from previous prime (1212316213) and next prime (1212316229).

It is not a de Polignac number, because 1212316221 - 2³ = 1212316213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1212316229) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 202052701 + ... + 202052706.

It is an arithmetic number, because the mean of its divisors is an integer number (404105408).

Almost surely, 2^1212316221 is an apocalyptic number.

It is an amenable number.

1212316221 is a deficient number, since it is larger than the sum of its proper divisors (404105411).

1212316221 is an equidigital number, since it uses as much as digits as its factorization.

1212316221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 404105410.

The product of its digits is 288, while the sum is 21.

The square root of 1212316221 is about 34818.3316803089. The cubic root of 1212316221 is about 1066.2817400910.

Adding to 1212316221 its reverse (1226132121), we get a palindrome (2438448342).

The spelling of 1212316221 in words is "one billion, two hundred twelve million, three hundred sixteen thousand, two hundred twenty-one".