1531243213 has 4 divisors (see below), whose sum is σ = 1531752768. Its totient is φ = 1530733660.

The previous prime is 1531243211. The next prime is 1531243237. The reversal of 1531243213 is 3123421351.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 3123421351 = 24197 ⋅129083.

It is a cyclic number.

It is not a de Polignac number, because 1531243213 - 2¹ = 1531243211 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1531243211) 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 in 3 ways as a sum of consecutive naturals, for example, 250243 + ... + 256288.

It is an arithmetic number, because the mean of its divisors is an integer number (382938192).

Almost surely, 2^1531243213 is an apocalyptic number.

It is an amenable number.

1531243213 is a deficient number, since it is larger than the sum of its proper divisors (509555).

1531243213 is an equidigital number, since it uses as much as digits as its factorization.

1531243213 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 509554.

The product of its digits is 2160, while the sum is 25.

The square root of 1531243213 is about 39131.1028850453. The cubic root of 1531243213 is about 1152.6073700988.

Adding to 1531243213 its reverse (3123421351), we get a palindrome (4654664564).

The spelling of 1531243213 in words is "one billion, five hundred thirty-one million, two hundred forty-three thousand, two hundred thirteen".