1665457920 has 432 divisors, whose sum is σ = 6938480640. Its totient is φ = 360308736.

The previous prime is 1665457891. The next prime is 1665457933. The reversal of 1665457920 is 297545661.

1665457920 is a `hidden beast` number, since 1 + 6 + 6 + 54 + 579 + 20 = 666.

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 pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 1531617 + ... + 1532703.

Almost surely, 2^1665457920 is an apocalyptic number.

1665457920 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 1665457920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3469240320).

1665457920 is an abundant number, since it is smaller than the sum of its proper divisors (5273022720).

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

1665457920 is a wasteful number, since it uses less digits than its factorization.

1665457920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1140 (or 1123 counting only the distinct ones).

The product of its (nonzero) digits is 453600, while the sum is 45.

The square root of 1665457920 is about 40810.0222984502. The cubic root of 1665457920 is about 1185.3444066489.

The spelling of 1665457920 in words is "one billion, six hundred sixty-five million, four hundred fifty-seven thousand, nine hundred twenty".