1661036544000 has 2400 divisors, whose sum is σ = 7125233955840. Its totient is φ = 382205952000.

The previous prime is 1661036543987. The next prime is 1661036544001. The reversal of 1661036544000 is 4456301661.

It is a happy number.

1661036544000 is a `hidden beast` number, since 1 + 6 + 6 + 103 + 6 + 544 + 0 + 0 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (2400).

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

It is not an unprimeable number, because it can be changed into a prime (1661036544001) by changing a digit.

It is a polite number, since it can be written in 159 ways as a sum of consecutive naturals, for example, 53581823985 + ... + 53581824015.

Almost surely, 2^{1661036544000} is an apocalyptic number.

1661036544000 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 1661036544000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3562616977920).

1661036544000 is an abundant number, since it is smaller than the sum of its proper divisors (5464197411840).

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

1661036544000 is an equidigital number, since it uses as much as digits as its factorization.

1661036544000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 122 (or 77 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 36.

The spelling of 1661036544000 in words is "one trillion, six hundred sixty-one billion, thirty-six million, five hundred forty-four thousand".