1861042840 has 64 divisors (see below), whose sum is σ = 4330609920. Its totient is φ = 719040000.

The previous prime is 1861042811. The next prime is 1861042889. The reversal of 1861042840 is 482401681.

It is a junction number, because it is equal to n+sod(n) for n = 1861042796 and 1861042805.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 868170 + ... + 870310.

It is an arithmetic number, because the mean of its divisors is an integer number (67665780).

Almost surely, 2^1861042840 is an apocalyptic number.

1861042840 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 1861042840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (2165304960).

1861042840 is an abundant number, since it is smaller than the sum of its proper divisors (2469567080).

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

1861042840 is a wasteful number, since it uses less digits than its factorization.

1861042840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2884 (or 2880 counting only the distinct ones).

The product of its (nonzero) digits is 12288, while the sum is 34.

The square root of 1861042840 is about 43139.8057482877. The cubic root of 1861042840 is about 1230.0387411509.

The spelling of 1861042840 in words is "one billion, eight hundred sixty-one million, forty-two thousand, eight hundred forty".