1215668281 has 4 divisors (see below), whose sum is σ = 1215818100. Its totient is φ = 1215518464.

The previous prime is 1215668269. The next prime is 1215668287. The reversal of 1215668281 is 1828665121.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 267028281 + 948640000 = 16341^2 + 30800^2 .

It is a cyclic number.

It is not a de Polignac number, because 1215668281 - 2⁹ = 1215667769 is a prime.

It is a super-2 number, since 2×1215668281² = 2955698738858989922, which contains 22 as substring.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1215668287) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 61996 + ... + 79213.

It is an arithmetic number, because the mean of its divisors is an integer number (303954525).

Almost surely, 2^1215668281 is an apocalyptic number.

It is an amenable number.

1215668281 is a deficient number, since it is larger than the sum of its proper divisors (149819).

1215668281 is an equidigital number, since it uses as much as digits as its factorization.

1215668281 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149818.

The product of its digits is 46080, while the sum is 40.

The square root of 1215668281 is about 34866.4348765399. The cubic root of 1215668281 is about 1067.2635936963.

The spelling of 1215668281 in words is "one billion, two hundred fifteen million, six hundred sixty-eight thousand, two hundred eighty-one".