1861891406010 has 48 divisors (see below), whose sum is σ = 4871751563016. Its totient is φ = 493341922944.

The previous prime is 1861891406009. The next prime is 1861891406017. The reversal of 1861891406010 is 106041981681.

It is a happy number.

1861891406010 is a `hidden beast` number, since 1 + 8 + 618 + 9 + 14 + 0 + 6 + 0 + 10 = 666.

It can be written as a sum of positive squares in 4 ways, for example, as 991340826921 + 870550579089 = 995661^2 + 933033^2 .

It is a Harshad number since it is a multiple of its sum of digits (45).

It is not an unprimeable number, because it can be changed into a prime (1861891406017) 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 23 ways as a sum of consecutive naturals, for example, 65870209 + ... + 65898468.

Almost surely, 2^{1861891406010} is an apocalyptic number.

1861891406010 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

1861891406010 is an abundant number, since it is smaller than the sum of its proper divisors (3009860157006).

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

1861891406010 is a wasteful number, since it uses less digits than its factorization.

1861891406010 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 131768847 (or 131768844 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 45.

The spelling of 1861891406010 in words is "one trillion, eight hundred sixty-one billion, eight hundred ninety-one million, four hundred six thousand, ten".