11215121557 has 2 divisors, whose sum is σ = 11215121558. Its totient is φ = 11215121556.

The previous prime is 11215121549. The next prime is 11215121569. The reversal of 11215121557 is 75512151211.

11215121557 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 8783250961 + 2431870596 = 93719^2 + 49314^2 .

It is a cyclic number.

It is not a de Polignac number, because 11215121557 - 2³ = 11215121549 is a prime.

It is a super-2 number, since 2×11215121557² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (11215121257) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5607560778 + 5607560779.

It is an arithmetic number, because the mean of its divisors is an integer number (5607560779).

Almost surely, 2^11215121557 is an apocalyptic number.

It is an amenable number.

11215121557 is a deficient number, since it is larger than the sum of its proper divisors (1).

11215121557 is an equidigital number, since it uses as much as digits as its factorization.

11215121557 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 3500, while the sum is 31.

Adding to 11215121557 its reverse (75512151211), we get a palindrome (86727272768).

The spelling of 11215121557 in words is "eleven billion, two hundred fifteen million, one hundred twenty-one thousand, five hundred fifty-seven".