1661155808 has 48 divisors (see below), whose sum is σ = 3561621840. Its totient is φ = 758055936.

The previous prime is 1661155789. The next prime is 1661155813. The reversal of 1661155808 is 8085511661.

It is a zygodrome in base 2.

It is a congruent number.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 14591 + ... + 59457.

It is an arithmetic number, because the mean of its divisors is an integer number (74200455).

Almost surely, 2^1661155808 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1661155808, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1780810920).

1661155808 is an abundant number, since it is smaller than the sum of its proper divisors (1900466032).

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

1661155808 is a wasteful number, since it uses less digits than its factorization.

1661155808 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 44979 (or 44971 counting only the distinct ones).

The product of its (nonzero) digits is 57600, while the sum is 41.

The square root of 1661155808 is about 40757.2792026161. The cubic root of 1661155808 is about 1184.3228894749.

The spelling of 1661155808 in words is "one billion, six hundred sixty-one million, one hundred fifty-five thousand, eight hundred eight".