1665774720 has 192 divisors, whose sum is σ = 5965727040. Its totient is φ = 444165120.

The previous prime is 1665774689. The next prime is 1665774757. The reversal of 1665774720 is 274775661.

1665774720 is a `hidden beast` number, since 1 + 6 + 6 + 577 + 4 + 72 + 0 = 666.

It is a tau number, because it is divible by the number of its divisors (192).

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

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 150165 + ... + 160875.

It is an arithmetic number, because the mean of its divisors is an integer number (31071495).

Almost surely, 2^1665774720 is an apocalyptic number.

1665774720 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 1665774720, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2982863520).

1665774720 is an abundant number, since it is smaller than the sum of its proper divisors (4299952320).

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

1665774720 is an equidigital number, since it uses as much as digits as its factorization.

1665774720 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10745 (or 10721 counting only the distinct ones).

The product of its (nonzero) digits is 493920, while the sum is 45.

The square root of 1665774720 is about 40813.9035133862. The cubic root of 1665774720 is about 1185.4195598136.

The spelling of 1665774720 in words is "one billion, six hundred sixty-five million, seven hundred seventy-four thousand, seven hundred twenty".