21121100212 has 6 divisors (see below), whose sum is σ = 36961925378. Its totient is φ = 10560550104.

The previous prime is 21121100173. The next prime is 21121100227. The reversal of 21121100212 is 21200112112.

It can be written as a sum of positive squares in only one way, i.e., 21093495696 + 27604516 = 145236^2 + 5254^2 .

It is a super-2 number, since 2×21121100212² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21121100192 and 21121100201.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2640137523 + ... + 2640137530.

Almost surely, 2^21121100212 is an apocalyptic number.

It is an amenable number.

21121100212 is a deficient number, since it is larger than the sum of its proper divisors (15840825166).

21121100212 is a wasteful number, since it uses less digits than its factorization.

21121100212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5280275057 (or 5280275055 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21121100212 its reverse (21200112112), we get a palindrome (42321212324).

The spelling of 21121100212 in words is "twenty-one billion, one hundred twenty-one million, one hundred thousand, two hundred twelve".