1661204160 has 672 divisors, whose sum is σ = 7394204160. Its totient is φ = 343664640.

The previous prime is 1661204131. The next prime is 1661204183. The reversal of 1661204160 is 614021661.

1661204160 is a `hidden beast` number, since 1 + 6 + 612 + 0 + 41 + 6 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (672).

It is a super-2 number, since 2×1661204160² = 5519198522402611200, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 7317967 + ... + 7318193.

It is an arithmetic number, because the mean of its divisors is an integer number (11003280).

Almost surely, 2^1661204160 is an apocalyptic number.

1661204160 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 1661204160, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3697102080).

1661204160 is an abundant number, since it is smaller than the sum of its proper divisors (5733000000).

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

1661204160 is a wasteful number, since it uses less digits than its factorization.

1661204160 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 282 (or 255 counting only the distinct ones).

The product of its (nonzero) digits is 1728, while the sum is 27.

The square root of 1661204160 is about 40757.8723684149. The cubic root of 1661204160 is about 1184.3343802342.

The spelling of 1661204160 in words is "one billion, six hundred sixty-one million, two hundred four thousand, one hundred sixty".