1661608000 has 168 divisors, whose sum is σ = 4459483080. Its totient is φ = 613017600.

The previous prime is 1661607991. The next prime is 1661608019. The reversal of 1661608000 is 8061661.

It can be written as a sum of positive squares in 12 ways, for example, as 1254859776 + 406748224 = 35424^2 + 20168^2 .

It is a super-2 number, since 2×1661608000² = 5521882291328000000, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1661608000.

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, 1351386 + ... + 1352614.

Almost surely, 2^1661608000 is an apocalyptic number.

1661608000 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 1661608000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2229741540).

1661608000 is an abundant number, since it is smaller than the sum of its proper divisors (2797875080).

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

1661608000 is a wasteful number, since it uses less digits than its factorization.

1661608000 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1282 (or 1249 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 28.

The square root of 1661608000 is about 40762.8262023133. The cubic root of 1661608000 is about 1184.4303433225.

Adding to 1661608000 its reverse (8061661), we get a palindrome (1669669661).

The spelling of 1661608000 in words is "one billion, six hundred sixty-one million, six hundred eight thousand".