1661299200000 has 2496 divisors, whose sum is σ = 7371428198400. Its totient is φ = 364953600000.

The previous prime is 1661299199993. The next prime is 1661299200013. The reversal of 1661299200000 is 29921661.

1661299200000 is a `hidden beast` number, since 16 + 612 + 9 + 9 + 20 + 0 + 0 + 0 + 0 = 666.

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

It is an unprimeable number.

It is a polite number, since it can be written in 191 ways as a sum of consecutive naturals, for example, 72230399989 + ... + 72230400011.

Almost surely, 2^{1661299200000} is an apocalyptic number.

1661299200000 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 1661299200000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3685714099200).

1661299200000 is an abundant number, since it is smaller than the sum of its proper divisors (5710128998400).

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

1661299200000 is an equidigital number, since it uses as much as digits as its factorization.

1661299200000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 111 (or 63 counting only the distinct ones).

The product of its (nonzero) digits is 11664, while the sum is 36.

The spelling of 1661299200000 in words is "one trillion, six hundred sixty-one billion, two hundred ninety-nine million, two hundred thousand".