1215661136 has 80 divisors (see below), whose sum is σ = 2507839488. Its totient is φ = 569712000.

The previous prime is 1215661099. The next prime is 1215661163. The reversal of 1215661136 is 6311665121.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 7279325 + ... + 7279491.

Almost surely, 2^1215661136 is an apocalyptic number.

1215661136 is a gapful number since it is divisible by the number (16) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1215661136, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1253919744).

1215661136 is an abundant number, since it is smaller than the sum of its proper divisors (1292178352).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

1215661136 is a wasteful number, since it uses less digits than its factorization.

1215661136 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 480 (or 474 counting only the distinct ones).

The product of its digits is 6480, while the sum is 32.

The square root of 1215661136 is about 34866.3324139491. The cubic root of 1215661136 is about 1067.2615027713.

The spelling of 1215661136 in words is "one billion, two hundred fifteen million, six hundred sixty-one thousand, one hundred thirty-six".