21121011012 has 12 divisors (see below), whose sum is σ = 49282359056. Its totient is φ = 7040337000.

The previous prime is 21121011007. The next prime is 21121011013. The reversal of 21121011012 is 21011012112.

It is a tau number, because it is divible by the number of its divisors (12).

It is a Harshad number since it is a multiple of its sum of digits (12), and also a Moran number because the ratio is a prime number: 1760084251 = 21121011012 / (2 + 1 + 1 + 2 + 1 + 0 + 1 + 1 + 0 + 1 + 2).

It is not an unprimeable number, because it can be changed into a prime (21121011013) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 880042114 + ... + 880042137.

Almost surely, 2^21121011012 is an apocalyptic number.

It is an amenable number.

21121011012 is an abundant number, since it is smaller than the sum of its proper divisors (28161348044).

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

21121011012 is a wasteful number, since it uses less digits than its factorization.

21121011012 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1760084258 (or 1760084256 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 12.

Adding to 21121011012 its reverse (21011012112), we get a palindrome (42132023124).

It can be divided in two parts, 211210 and 11012, that added together give a palindrome (222222).

The spelling of 21121011012 in words is "twenty-one billion, one hundred twenty-one million, eleven thousand, twelve".