1215551331541 has 2 divisors, whose sum is σ = 1215551331542. Its totient is φ = 1215551331540.

The previous prime is 1215551331523. The next prime is 1215551331563. The reversal of 1215551331541 is 1451331555121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1146634056100 + 68917275441 = 1070810^2 + 262521^2 .

It is a cyclic number.

It is not a de Polignac number, because 1215551331541 - 2⁵ = 1215551331509 is a prime.

It is a super-2 number, since 2×1215551331541² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1215551331541.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1215551331571) 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, 607775665770 + 607775665771.

It is an arithmetic number, because the mean of its divisors is an integer number (607775665771).

Almost surely, 2^{1215551331541} is an apocalyptic number.

It is an amenable number.

1215551331541 is a deficient number, since it is larger than the sum of its proper divisors (1).

1215551331541 is an equidigital number, since it uses as much as digits as its factorization.

1215551331541 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 45000, while the sum is 37.

Adding to 1215551331541 its reverse (1451331555121), we get a palindrome (2666882886662).

The spelling of 1215551331541 in words is "one trillion, two hundred fifteen billion, five hundred fifty-one million, three hundred thirty-one thousand, five hundred forty-one".