1861866216 has 128 divisors (see below), whose sum is σ = 5999232000. Its totient is φ = 523993536.

The previous prime is 1861866191. The next prime is 1861866239. The reversal of 1861866216 is 6126681681.

1861866216 is a `hidden beast` number, since 1 + 8 + 6 + 18 + 6 + 621 + 6 = 666.

It is a nude number because it is divisible by every one of its digits.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 92115 + ... + 110493.

It is an arithmetic number, because the mean of its divisors is an integer number (46869000).

Almost surely, 2^1861866216 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 1861866216, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2999616000).

1861866216 is an abundant number, since it is smaller than the sum of its proper divisors (4137365784).

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

1861866216 is a wasteful number, since it uses less digits than its factorization.

1861866216 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18468 (or 18458 counting only the distinct ones).

The product of its digits is 165888, while the sum is 45.

The square root of 1861866216 is about 43149.3478050364. The cubic root of 1861866216 is about 1230.2201152766.

The spelling of 1861866216 in words is "one billion, eight hundred sixty-one million, eight hundred sixty-six thousand, two hundred sixteen".