1665578880 has 384 divisors, whose sum is σ = 6654398400. Its totient is φ = 376012800.

The previous prime is 1665578861. The next prime is 1665578891. The reversal of 1665578880 is 888755661.

1665578880 is a `hidden beast` number, since 1 + 6 + 6 + 557 + 8 + 8 + 80 = 666.

It is a tau number, because it is divible by the number of its divisors (384).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 4072116 + ... + 4072524.

Almost surely, 2^1665578880 is an apocalyptic number.

1665578880 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 1665578880, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3327199200).

1665578880 is an abundant number, since it is smaller than the sum of its proper divisors (4988819520).

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

1665578880 is a wasteful number, since it uses less digits than its factorization.

1665578880 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 542 (or 527 counting only the distinct ones).

The product of its (nonzero) digits is 3225600, while the sum is 54.

The square root of 1665578880 is about 40811.5042604411. The cubic root of 1665578880 is about 1185.3731026182.

The spelling of 1665578880 in words is "one billion, six hundred sixty-five million, five hundred seventy-eight thousand, eight hundred eighty".