1661665852 has 72 divisors (see below), whose sum is σ = 3753025920. Its totient is φ = 636380640.

The previous prime is 1661665781. The next prime is 1661665891. The reversal of 1661665852 is 2585661661.

It is a super-2 number, since 2×1661665852² = 5522266807405771808, which contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 120673 + ... + 133735.

It is an arithmetic number, because the mean of its divisors is an integer number (52125360).

Almost surely, 2^1661665852 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 1661665852, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1876512960).

1661665852 is an abundant number, since it is smaller than the sum of its proper divisors (2091360068).

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

1661665852 is a wasteful number, since it uses less digits than its factorization.

1661665852 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13151 (or 13142 counting only the distinct ones).

The product of its digits is 518400, while the sum is 46.

The square root of 1661665852 is about 40763.5358132731. The cubic root of 1661665852 is about 1184.4440892179. Note that the first 3 decimals are identical.

The spelling of 1661665852 in words is "one billion, six hundred sixty-one million, six hundred sixty-five thousand, eight hundred fifty-two".