1213211557 has 2 divisors, whose sum is σ = 1213211558. Its totient is φ = 1213211556.

The previous prime is 1213211551. The next prime is 1213211591. The reversal of 1213211557 is 7551123121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1213198561 + 12996 = 34831^2 + 114^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1213211557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1213211551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606605778 + 606605779.

It is an arithmetic number, because the mean of its divisors is an integer number (606605779).

Almost surely, 2^1213211557 is an apocalyptic number.

It is an amenable number.

1213211557 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213211557 is an equidigital number, since it uses as much as digits as its factorization.

1213211557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 2100, while the sum is 28.

The square root of 1213211557 is about 34831.1865574516. The cubic root of 1213211557 is about 1066.5441703840.

Adding to 1213211557 its reverse (7551123121), we get a palindrome (8764334678).

The spelling of 1213211557 in words is "one billion, two hundred thirteen million, two hundred eleven thousand, five hundred fifty-seven".