1531312121 has 2 divisors, whose sum is σ = 1531312122. Its totient is φ = 1531312120.

The previous prime is 1531312109. The next prime is 1531312169. The reversal of 1531312121 is 1212131351.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1083397225 + 447914896 = 32915^2 + 21164^2 .

It is an emirp because it is prime and its reverse (1212131351) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1531312121 - 2¹⁰ = 1531311097 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 1531312093 and 1531312102.

It is not a weakly prime, because it can be changed into another prime (1531312171) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 765656060 + 765656061.

It is an arithmetic number, because the mean of its divisors is an integer number (765656061).

Almost surely, 2^1531312121 is an apocalyptic number.

It is an amenable number.

1531312121 is a deficient number, since it is larger than the sum of its proper divisors (1).

1531312121 is an equidigital number, since it uses as much as digits as its factorization.

1531312121 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 180, while the sum is 20.

The square root of 1531312121 is about 39131.9833512180. The cubic root of 1531312121 is about 1152.6246594658.

Adding to 1531312121 its reverse (1212131351), we get a palindrome (2743443472).

The spelling of 1531312121 in words is "one billion, five hundred thirty-one million, three hundred twelve thousand, one hundred twenty-one".