1865666540 has 24 divisors (see below), whose sum is σ = 4023790512. Its totient is φ = 726096960.

The previous prime is 1865666533. The next prime is 1865666549. The reversal of 1865666540 is 456665681.

It is not an unprimeable number, because it can be changed into a prime (1865666549) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1259846 + ... + 1261325.

It is an arithmetic number, because the mean of its divisors is an integer number (167657938).

Almost surely, 2^1865666540 is an apocalyptic number.

1865666540 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1865666540 is an abundant number, since it is smaller than the sum of its proper divisors (2158123972).

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

1865666540 is a wasteful number, since it uses less digits than its factorization.

1865666540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2521217 (or 2521215 counting only the distinct ones).

The product of its (nonzero) digits is 1036800, while the sum is 47.

The square root of 1865666540 is about 43193.3622215266. The cubic root of 1865666540 is about 1231.0565623603.

The spelling of 1865666540 in words is "one billion, eight hundred sixty-five million, six hundred sixty-six thousand, five hundred forty".