1866191240 has 64 divisors (see below), whose sum is σ = 4284792000. Its totient is φ = 731301120.

The previous prime is 1866191221. The next prime is 1866191251. The reversal of 1866191240 is 421916681.

It is a junction number, because it is equal to n+sod(n) for n = 1866191194 and 1866191203.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 779966 + ... + 782354.

It is an arithmetic number, because the mean of its divisors is an integer number (66949875).

Almost surely, 2^1866191240 is an apocalyptic number.

1866191240 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 1866191240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2142396000).

1866191240 is an abundant number, since it is smaller than the sum of its proper divisors (2418600760).

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

1866191240 is a wasteful number, since it uses less digits than its factorization.

1866191240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2790 (or 2786 counting only the distinct ones).

The product of its (nonzero) digits is 20736, while the sum is 38.

The square root of 1866191240 is about 43199.4356444618. The cubic root of 1866191240 is about 1231.1719589795.

It can be divided in two parts, 18661 and 91240, that added together give a palindrome (109901).

The spelling of 1866191240 in words is "one billion, eight hundred sixty-six million, one hundred ninety-one thousand, two hundred forty".