1215231551 has 2 divisors, whose sum is σ = 1215231552. Its totient is φ = 1215231550.

The previous prime is 1215231491. The next prime is 1215231571. The reversal of 1215231551 is 1551325121.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1215231551 - 2⁶ = 1215231487 is a prime.

It is a Sophie Germain prime.

It is a self number, because there is not a number n which added to its sum of digits gives 1215231551.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1215231571) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 607615775 + 607615776.

It is an arithmetic number, because the mean of its divisors is an integer number (607615776).

Almost surely, 2^1215231551 is an apocalyptic number.

1215231551 is a deficient number, since it is larger than the sum of its proper divisors (1).

1215231551 is an equidigital number, since it uses as much as digits as its factorization.

1215231551 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1500, while the sum is 26.

The square root of 1215231551 is about 34860.1714138069. The cubic root of 1215231551 is about 1067.1357732307.

Adding to 1215231551 its reverse (1551325121), we get a palindrome (2766556672).

The spelling of 1215231551 in words is "one billion, two hundred fifteen million, two hundred thirty-one thousand, five hundred fifty-one".