1213500221 has 2 divisors, whose sum is σ = 1213500222. Its totient is φ = 1213500220.

The previous prime is 1213500199. The next prime is 1213500229. The reversal of 1213500221 is 1220053121.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 923308996 + 290191225 = 30386^2 + 17035^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213500221 - 2³⁰ = 139758397 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1213500221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1213500229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606750110 + 606750111.

It is an arithmetic number, because the mean of its divisors is an integer number (606750111).

Almost surely, 2^1213500221 is an apocalyptic number.

It is an amenable number.

1213500221 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213500221 is an equidigital number, since it uses as much as digits as its factorization.

1213500221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 120, while the sum is 17.

The square root of 1213500221 is about 34835.3300687678. The cubic root of 1213500221 is about 1066.6287526346.

Adding to 1213500221 its reverse (1220053121), we get a palindrome (2433553342).

The spelling of 1213500221 in words is "one billion, two hundred thirteen million, five hundred thousand, two hundred twenty-one".