1215318261 has 16 divisors (see below), whose sum is σ = 1708784640. Its totient is φ = 766185840.

The previous prime is 1215318233. The next prime is 1215318263. The reversal of 1215318261 is 1628135121.

It is not a de Polignac number, because 1215318261 - 2⁷ = 1215318133 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1215318263) 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 15 ways as a sum of consecutive naturals, for example, 13156 + ... + 51026.

It is an arithmetic number, because the mean of its divisors is an integer number (106799040).

Almost surely, 2^1215318261 is an apocalyptic number.

It is an amenable number.

1215318261 is a deficient number, since it is larger than the sum of its proper divisors (493466379).

1215318261 is a wasteful number, since it uses less digits than its factorization.

1215318261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 38456.

The product of its digits is 2880, while the sum is 30.

The square root of 1215318261 is about 34861.4150745491. The cubic root of 1215318261 is about 1067.1611536180.

The spelling of 1215318261 in words is "one billion, two hundred fifteen million, three hundred eighteen thousand, two hundred sixty-one".