18871021810 has 16 divisors (see below), whose sum is σ = 35139144600. Its totient is φ = 7288118656.

The previous prime is 18871021801. The next prime is 18871021811. The reversal of 18871021810 is 1812017881.

It can be written as a sum of positive squares in 4 ways, for example, as 18543085929 + 327935881 = 136173^2 + 18109^2 .

It is a super-4 number, since 4×18871021810⁴ (a number of 42 digits) contains 4444 as substring. Note that it is a super-d number also for d = 2.

It is a self number, because there is not a number n which added to its sum of digits gives 18871021810.

It is not an unprimeable number, because it can be changed into a prime (18871021811) 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 7 ways as a sum of consecutive naturals, for example, 32535955 + ... + 32536534.

Almost surely, 2^18871021810 is an apocalyptic number.

18871021810 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

18871021810 is a deficient number, since it is larger than the sum of its proper divisors (16268122790).

18871021810 is a wasteful number, since it uses less digits than its factorization.

18871021810 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65072525.

The product of its (nonzero) digits is 7168, while the sum is 37.

The spelling of 18871021810 in words is "eighteen billion, eight hundred seventy-one million, twenty-one thousand, eight hundred ten".