1665602161920 has 1728 divisors, whose sum is σ = 6759014169600. Its totient is φ = 387142778880.

The previous prime is 1665602161891. The next prime is 1665602161943. The reversal of 1665602161920 is 291612065661.

1665602161920 is a `hidden beast` number, since 1 + 6 + 6 + 5 + 6 + 0 + 2 + 1 + 619 + 20 = 666.

It is a tau number, because it is divible by the number of its divisors (1728).

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a congruent number.

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, 12714520255 + ... + 12714520385.

Almost surely, 2^{1665602161920} is an apocalyptic number.

1665602161920 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 1665602161920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3379507084800).

1665602161920 is an abundant number, since it is smaller than the sum of its proper divisors (5093412007680).

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

1665602161920 is a wasteful number, since it uses less digits than its factorization.

1665602161920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 281 (or 244 counting only the distinct ones).

The product of its (nonzero) digits is 233280, while the sum is 45.

The spelling of 1665602161920 in words is "one trillion, six hundred sixty-five billion, six hundred two million, one hundred sixty-one thousand, nine hundred twenty".