1331665686 has 48 divisors (see below), whose sum is σ = 3120914160. Its totient is φ = 407937600.

The previous prime is 1331665681. The next prime is 1331665717. The reversal of 1331665686 is 6865661331.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1331665681) 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 23 ways as a sum of consecutive naturals, for example, 41161 + ... + 66011.

It is an arithmetic number, because the mean of its divisors is an integer number (65019045).

Almost surely, 2^1331665686 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1331665686, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1560457080).

1331665686 is an abundant number, since it is smaller than the sum of its proper divisors (1789248474).

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

1331665686 is a wasteful number, since it uses less digits than its factorization.

1331665686 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25101 (or 25098 counting only the distinct ones).

The product of its digits is 466560, while the sum is 45.

The square root of 1331665686 is about 36491.9948207823. The cubic root of 1331665686 is about 1100.1833540089.

The spelling of 1331665686 in words is "one billion, three hundred thirty-one million, six hundred sixty-five thousand, six hundred eighty-six".