1661655600 has 480 divisors, whose sum is σ = 6576007680. Its totient is φ = 395136000.

The previous prime is 1661655581. The next prime is 1661655641. The reversal of 1661655600 is 65561661.

It is a super-2 number, since 2×1661655600² = 5522198666022720000, which contains 22 as substring.

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

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 8434702 + ... + 8434898.

It is an arithmetic number, because the mean of its divisors is an integer number (13700016).

Almost surely, 2^1661655600 is an apocalyptic number.

1661655600 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 1661655600, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3288003840).

1661655600 is an abundant number, since it is smaller than the sum of its proper divisors (4914352080).

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

1661655600 is a wasteful number, since it uses less digits than its factorization.

1661655600 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 306 (or 289 counting only the distinct ones).

The product of its (nonzero) digits is 32400, while the sum is 36.

The square root of 1661655600 is about 40763.4100634380. The cubic root of 1661655600 is about 1184.4416533199.

It can be divided in two parts, 16 and 61655600, that added together give a palindrome (61655616).

The spelling of 1661655600 in words is "one billion, six hundred sixty-one million, six hundred fifty-five thousand, six hundred".