21121110212 has 6 divisors (see below), whose sum is σ = 36961942878. Its totient is φ = 10560555104.

The previous prime is 21121110211. The next prime is 21121110223. The reversal of 21121110212 is 21201112112.

It can be written as a sum of positive squares in only one way, i.e., 20821335616 + 299774596 = 144296^2 + 17314^2 .

It is a super-2 number, since 2×21121110212² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21121110211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2640138773 + ... + 2640138780.

It is an arithmetic number, because the mean of its divisors is an integer number (6160323813).

Almost surely, 2^21121110212 is an apocalyptic number.

It is an amenable number.

21121110212 is a deficient number, since it is larger than the sum of its proper divisors (15840832666).

21121110212 is a wasteful number, since it uses less digits than its factorization.

21121110212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5280277557 (or 5280277555 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21121110212 its reverse (21201112112), we get a palindrome (42322222324).

The spelling of 21121110212 in words is "twenty-one billion, one hundred twenty-one million, one hundred ten thousand, two hundred twelve".