1661085000000 has 336 divisors, whose sum is σ = 5951646287184. Its totient is φ = 442944000000.

The previous prime is 1661084999999. The next prime is 1661085000031. The reversal of 1661085000000 is 5801661.

It can be written as a sum of positive squares in 8 ways, for example, as 1628563927104 + 32521072896 = 1276152^2 + 180336^2 .

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 44981544 + ... + 45018456.

Almost surely, 2^{1661085000000} is an apocalyptic number.

1661085000000 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 1661085000000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2975823143592).

1661085000000 is an abundant number, since it is smaller than the sum of its proper divisors (4290561287184).

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

1661085000000 is an frugal number, since it uses more digits than its factorization.

1661085000000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 36966 (or 36923 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 27.

The spelling of 1661085000000 in words is "one trillion, six hundred sixty-one billion, eighty-five million", and thus it is an aban number.