1665666240 has 224 divisors, whose sum is σ = 6071030784. Its totient is φ = 379023360.

The previous prime is 1665666221. The next prime is 1665666241. The reversal of 1665666240 is 426665661.

It is a happy number.

It is a tau number, because it is divible by the number of its divisors (224).

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 1665666192 and 1665666201.

It is not an unprimeable number, because it can be changed into a prime (1665666241) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2089522 + ... + 2090318.

It is an arithmetic number, because the mean of its divisors is an integer number (27102816).

Almost surely, 2^1665666240 is an apocalyptic number.

1665666240 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 1665666240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (3035515392).

1665666240 is an abundant number, since it is smaller than the sum of its proper divisors (4405364544).

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

1665666240 is a wasteful number, since it uses less digits than its factorization.

1665666240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1135 (or 1125 counting only the distinct ones).

The product of its (nonzero) digits is 311040, while the sum is 42.

The square root of 1665666240 is about 40812.5745328569. The cubic root of 1665666240 is about 1185.3938266210.

The spelling of 1665666240 in words is "one billion, six hundred sixty-five million, six hundred sixty-six thousand, two hundred forty".