1866840920 has 128 divisors (see below), whose sum is σ = 4953692160. Its totient is φ = 619799040.

The previous prime is 1866840881. The next prime is 1866840923. The reversal of 1866840920 is 290486681.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1866840923) 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, 3801875 + ... + 3802365.

It is an arithmetic number, because the mean of its divisors is an integer number (38700720).

Almost surely, 2^1866840920 is an apocalyptic number.

1866840920 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 1866840920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2476846080).

1866840920 is an abundant number, since it is smaller than the sum of its proper divisors (3086851240).

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

1866840920 is a wasteful number, since it uses less digits than its factorization.

1866840920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 913 (or 909 counting only the distinct ones).

The product of its (nonzero) digits is 165888, while the sum is 44.

The square root of 1866840920 is about 43206.9545328064. The cubic root of 1866840920 is about 1231.3148123269.

The spelling of 1866840920 in words is "one billion, eight hundred sixty-six million, eight hundred forty thousand, nine hundred twenty".