21811011812 has 48 divisors (see below), whose sum is σ = 38984742720. Its totient is φ = 10675728000.

The previous prime is 21811011811. The next prime is 21811011823.

21811011812 is nontrivially palindromic in base 10.

It is not an unprimeable number, because it can be changed into a prime (21811011811) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 14245487 + ... + 14247017.

It is an arithmetic number, because the mean of its divisors is an integer number (812182140).

Almost surely, 2^21811011812 is an apocalyptic number.

It is an amenable number.

21811011812 is a deficient number, since it is larger than the sum of its proper divisors (17173730908).

21811011812 is a wasteful number, since it uses less digits than its factorization.

21811011812 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2012 (or 2010 counting only the distinct ones).

The product of its (nonzero) digits is 256, while the sum is 26.

It can be divided in two parts, 218110 and 11812, that added together give a palindrome (229922).

The spelling of 21811011812 in words is "twenty-one billion, eight hundred eleven million, eleven thousand, eight hundred twelve".