1661433660 has 96 divisors (see below), whose sum is σ = 5202093120. Its totient is φ = 440204544.

The previous prime is 1661433643. The next prime is 1661433667. The reversal of 1661433660 is 663341661.

1661433660 is a `hidden beast` number, since 1 + 6 + 614 + 3 + 36 + 6 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1661433667) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 74982 + ... + 94578.

It is an arithmetic number, because the mean of its divisors is an integer number (54188470).

Almost surely, 2^1661433660 is an apocalyptic number.

1661433660 is a gapful number since it is divisible by the number (10) 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 1661433660, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2601046560).

1661433660 is an abundant number, since it is smaller than the sum of its proper divisors (3540659460).

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

1661433660 is a wasteful number, since it uses less digits than its factorization.

1661433660 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19772 (or 19764 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 36.

The square root of 1661433660 is about 40760.6876782029. The cubic root of 1661433660 is about 1184.3889174250.

The spelling of 1661433660 in words is "one billion, six hundred sixty-one million, four hundred thirty-three thousand, six hundred sixty".