21081181875 has 160 divisors (see below), whose sum is σ = 40777347072. Its totient is φ = 9599040000.

The previous prime is 21081181871. The next prime is 21081181883. The reversal of 21081181875 is 57818118012.

It is not a de Polignac number, because 21081181875 - 2² = 21081181871 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21081181871) 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 159 ways as a sum of consecutive naturals, for example, 17378769 + ... + 17379981.

Almost surely, 2^21081181875 is an apocalyptic number.

21081181875 is a gapful number since it is divisible by the number (25) formed by its first and last digit.

21081181875 is a deficient number, since it is larger than the sum of its proper divisors (19696165197).

21081181875 is a wasteful number, since it uses less digits than its factorization.

21081181875 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1303 (or 1288 counting only the distinct ones).

The product of its (nonzero) digits is 35840, while the sum is 42.

Adding to 21081181875 its reverse (57818118012), we get a palindrome (78899299887).

The spelling of 21081181875 in words is "twenty-one billion, eighty-one million, one hundred eighty-one thousand, eight hundred seventy-five".