1861287120 has 960 divisors, whose sum is σ = 8708014080. Its totient is φ = 354585600.

The previous prime is 1861287107. The next prime is 1861287137. The reversal of 1861287120 is 217821681.

1861287120 is a `hidden beast` number, since 18 + 612 + 8 + 7 + 1 + 20 = 666.

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 191 ways as a sum of consecutive naturals, for example, 60041505 + ... + 60041535.

It is an arithmetic number, because the mean of its divisors is an integer number (9070848).

Almost surely, 2^1861287120 is an apocalyptic number.

1861287120 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 1861287120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (4354007040).

1861287120 is an abundant number, since it is smaller than the sum of its proper divisors (6846726960).

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

1861287120 is a wasteful number, since it uses less digits than its factorization.

1861287120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 109 (or 78 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 36.

The square root of 1861287120 is about 43142.6369152373. The cubic root of 1861287120 is about 1230.0925569850.

The spelling of 1861287120 in words is "one billion, eight hundred sixty-one million, two hundred eighty-seven thousand, one hundred twenty".