1861813800 has 864 divisors, whose sum is σ = 8434951200. Its totient is φ = 362880000.

The previous prime is 1861813783. The next prime is 1861813817. The reversal of 1861813800 is 83181681.

1861813800 is a `hidden beast` number, since 1 + 8 + 618 + 1 + 38 + 0 + 0 = 666.

It is an interprime number because it is at equal distance from previous prime (1861813783) and next prime (1861813817).

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 215 ways as a sum of consecutive naturals, for example, 18433750 + ... + 18433850.

It is an arithmetic number, because the mean of its divisors is an integer number (9762675).

Almost surely, 2^1861813800 is an apocalyptic number.

1861813800 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 1861813800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4217475600).

1861813800 is an abundant number, since it is smaller than the sum of its proper divisors (6573137400).

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

1861813800 is a wasteful number, since it uses less digits than its factorization.

1861813800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 167 (or 148 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 36.

The square root of 1861813800 is about 43148.7404219405. The cubic root of 1861813800 is about 1230.2085706193.

It can be divided in two parts, 186181 and 3800, that added together give a palindrome (189981).

The spelling of 1861813800 in words is "one billion, eight hundred sixty-one million, eight hundred thirteen thousand, eight hundred".