1665538560 has 480 divisors, whose sum is σ = 6894201600. Its totient is φ = 363331584.

The previous prime is 1665538547. The next prime is 1665538573. The reversal of 1665538560 is 658355661.

1665538560 is a `hidden beast` number, since 1 + 6 + 6 + 55 + 38 + 560 = 666.

It is an interprime number because it is at equal distance from previous prime (1665538547) and next prime (1665538573).

It is a tau number, because it is divible by the number of its divisors (480).

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 47 ways as a sum of consecutive naturals, for example, 3709216 + ... + 3709664.

It is an arithmetic number, because the mean of its divisors is an integer number (14362920).

Almost surely, 2^1665538560 is an apocalyptic number.

1665538560 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 1665538560, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3447100800).

1665538560 is an abundant number, since it is smaller than the sum of its proper divisors (5228663040).

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

1665538560 is a wasteful number, since it uses less digits than its factorization.

1665538560 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 508 (or 489 counting only the distinct ones).

The product of its (nonzero) digits is 648000, while the sum is 45.

The square root of 1665538560 is about 40811.0102790901. The cubic root of 1665538560 is about 1185.3635374495.

It can be divided in two parts, 1665 and 538560, that added together give a square (540225 = 735²).

The spelling of 1665538560 in words is "one billion, six hundred sixty-five million, five hundred thirty-eight thousand, five hundred sixty".