1215643131 has 6 divisors (see below), whose sum is σ = 1755928980. Its totient is φ = 810428748.

The previous prime is 1215643087. The next prime is 1215643151. The reversal of 1215643131 is 1313465121.

It is a happy number.

1215643131 is a `hidden beast` number, since 1 + 2 + 1 + 5 + 643 + 13 + 1 = 666.

It is not a de Polignac number, because 1215643131 - 2⁷ = 1215643003 is a prime.

It is a super-2 number, since 2×1215643131² = 2955576443894966322, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 1215643095 and 1215643104.

It is not an unprimeable number, because it can be changed into a prime (1215643151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 67535721 + ... + 67535738.

It is an arithmetic number, because the mean of its divisors is an integer number (292654830).

Almost surely, 2^1215643131 is an apocalyptic number.

1215643131 is a deficient number, since it is larger than the sum of its proper divisors (540285849).

1215643131 is a wasteful number, since it uses less digits than its factorization.

1215643131 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 135071465 (or 135071462 counting only the distinct ones).

The product of its digits is 2160, while the sum is 27.

The square root of 1215643131 is about 34866.0742126211. The cubic root of 1215643131 is about 1067.2562337213.

The spelling of 1215643131 in words is "one billion, two hundred fifteen million, six hundred forty-three thousand, one hundred thirty-one".