1861157200 has 180 divisors, whose sum is σ = 5235585660. Its totient is φ = 633937920.

The previous prime is 1861157197. The next prime is 1861157201. The reversal of 1861157200 is 27511681.

It can be written as a sum of positive squares in 6 ways, for example, as 355096336 + 1506060864 = 18844^2 + 38808^2 .

It is a super-2 number, since 2×1861157200² = 6927812246223680000, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1861157201) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 5272224 + ... + 5272576.

It is an arithmetic number, because the mean of its divisors is an integer number (29086587).

Almost surely, 2^1861157200 is an apocalyptic number.

1861157200 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 1861157200, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2617792830).

1861157200 is an abundant number, since it is smaller than the sum of its proper divisors (3374428460).

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

1861157200 is a wasteful number, since it uses less digits than its factorization.

1861157200 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 654 (or 636 counting only the distinct ones).

The product of its (nonzero) digits is 3360, while the sum is 31.

The square root of 1861157200 is about 43141.1311859112. The cubic root of 1861157200 is about 1230.0639356899.

Adding to 1861157200 its reverse (27511681), we get a palindrome (1888668881).

The spelling of 1861157200 in words is "one billion, eight hundred sixty-one million, one hundred fifty-seven thousand, two hundred".