1861120800 has 720 divisors, whose sum is σ = 8484581952. Its totient is φ = 385689600.

The previous prime is 1861120787. The next prime is 1861120801. The reversal of 1861120800 is 80211681.

It is a tau number, because it is divible by the number of its divisors (720).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is not an unprimeable number, because it can be changed into a prime (1861120801) by changing a digit.

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 119 ways as a sum of consecutive naturals, for example, 4989414 + ... + 4989786.

Almost surely, 2^1861120800 is an apocalyptic number.

1861120800 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 1861120800, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4242290976).

1861120800 is an abundant number, since it is smaller than the sum of its proper divisors (6623461152).

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

1861120800 is a wasteful number, since it uses less digits than its factorization.

1861120800 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 423 (or 401 counting only the distinct ones).

The product of its (nonzero) digits is 768, while the sum is 27.

The square root of 1861120800 is about 43140.7093126666. The cubic root of 1861120800 is about 1230.0559165537.

The spelling of 1861120800 in words is "one billion, eight hundred sixty-one million, one hundred twenty thousand, eight hundred".