1661151560640 has 448 divisors, whose sum is σ = 6202184712192. Its totient is φ = 371367936000.

The previous prime is 1661151560609. The next prime is 1661151560683. The reversal of 1661151560640 is 460651511661.

It is a junction number, because it is equal to n+sod(n) for n = 1661151560592 and 1661151560601.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 158004024 + ... + 158014536.

It is an arithmetic number, because the mean of its divisors is an integer number (13844162304).

Almost surely, 2^{1661151560640} is an apocalyptic number.

1661151560640 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 1661151560640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3101092356096).

1661151560640 is an abundant number, since it is smaller than the sum of its proper divisors (4541033151552).

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

1661151560640 is a wasteful number, since it uses less digits than its factorization.

1661151560640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11708 (or 11698 counting only the distinct ones).

The product of its (nonzero) digits is 129600, while the sum is 42.

The spelling of 1661151560640 in words is "one trillion, six hundred sixty-one billion, one hundred fifty-one million, five hundred sixty thousand, six hundred forty".