1215431313 has 4 divisors (see below), whose sum is σ = 1620575088. Its totient is φ = 810287540.

The previous prime is 1215431281. The next prime is 1215431323. The reversal of 1215431313 is 3131345121.

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: 3131345121 = 3 ⋅1043781707.

It is a cyclic number.

It is not a de Polignac number, because 1215431313 - 2⁵ = 1215431281 is a prime.

It is not an unprimeable number, because it can be changed into a prime (1215431323) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 202571883 + ... + 202571888.

It is an arithmetic number, because the mean of its divisors is an integer number (405143772).

Almost surely, 2^1215431313 is an apocalyptic number.

It is an amenable number.

1215431313 is a deficient number, since it is larger than the sum of its proper divisors (405143775).

1215431313 is an equidigital number, since it uses as much as digits as its factorization.

1215431313 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 405143774.

The product of its digits is 1080, while the sum is 24.

The square root of 1215431313 is about 34863.0364856534. The cubic root of 1215431313 is about 1067.1942426082.

Adding to 1215431313 its reverse (3131345121), we get a palindrome (4346776434).

The spelling of 1215431313 in words is "one billion, two hundred fifteen million, four hundred thirty-one thousand, three hundred thirteen".