1665639360 has 1008 divisors, whose sum is σ = 7724302560. Its totient is φ = 325140480.

The previous prime is 1665639341. The next prime is 1665639383. The reversal of 1665639360 is 639365661.

1665639360 is a `hidden beast` number, since 1 + 6 + 6 + 5 + 639 + 3 + 6 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (1008).

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 143 ways as a sum of consecutive naturals, for example, 45017262 + ... + 45017298.

Almost surely, 2^1665639360 is an apocalyptic number.

1665639360 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 1665639360, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3862151280).

1665639360 is an abundant number, since it is smaller than the sum of its proper divisors (6058663200).

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

1665639360 is a wasteful number, since it uses less digits than its factorization.

1665639360 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114 (or 94 counting only the distinct ones).

The product of its (nonzero) digits is 524880, while the sum is 45.

The square root of 1665639360 is about 40812.2452212568. The cubic root of 1665639360 is about 1185.3874500819.

The spelling of 1665639360 in words is "one billion, six hundred sixty-five million, six hundred thirty-nine thousand, three hundred sixty".