1665239040 has 384 divisors, whose sum is σ = 6250608000. Its totient is φ = 419364864.

The previous prime is 1665239033. The next prime is 1665239053. The reversal of 1665239040 is 409325661.

It is a happy number.

1665239040 is a `hidden beast` number, since 1 + 6 + 6 + 523 + 90 + 40 = 666.

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

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 1665238986 and 1665239004.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 5252962 + ... + 5253278.

It is an arithmetic number, because the mean of its divisors is an integer number (16277625).

Almost surely, 2^1665239040 is an apocalyptic number.

1665239040 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 1665239040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3125304000).

1665239040 is an abundant number, since it is smaller than the sum of its proper divisors (4585368960).

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

1665239040 is a wasteful number, since it uses less digits than its factorization.

1665239040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 372 (or 346 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 1665239040 is about 40807.3405161375. The cubic root of 1665239040 is about 1185.2924770770.

The spelling of 1665239040 in words is "one billion, six hundred sixty-five million, two hundred thirty-nine thousand, forty".