15531121 has 2 divisors, whose sum is σ = 15531122. Its totient is φ = 15531120.

The previous prime is 15531091. The next prime is 15531133. The reversal of 15531121 is 12113551.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14930496 + 600625 = 3864^2 + 775^2 .

It is a cyclic number.

It is not a de Polignac number, because 15531121 - 2⁷ = 15530993 is a prime.

It is not a weakly prime, because it can be changed into another prime (15531221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 7765560 + 7765561.

It is an arithmetic number, because the mean of its divisors is an integer number (7765561).

Almost surely, 2^15531121 is an apocalyptic number.

It is an amenable number.

15531121 is a deficient number, since it is larger than the sum of its proper divisors (1).

15531121 is an equidigital number, since it uses as much as digits as its factorization.

15531121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 150, while the sum is 19.

The square root of 15531121 is about 3940.9543260485. The cubic root of 15531121 is about 249.4983058855.

Adding to 15531121 its reverse (12113551), we get a palindrome (27644672).

The spelling of 15531121 in words is "fifteen million, five hundred thirty-one thousand, one hundred twenty-one".