21012121212 has 24 divisors (see below), whose sum is σ = 49043094912. Its totient is φ = 7001924400.

The previous prime is 21012121189. The next prime is 21012121213. The reversal of 21012121212 is 21212121012.

21012121212 is an esthetic number in base 10, because in such base its adjacent digits differ by 1.

It is an alternating number because its digits alternate between even and odd.

21012121212 is a modest number, since divided by 121212 gives 21012 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 21012121191 and 21012121200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012121213) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 222864 + ... + 302807.

It is an arithmetic number, because the mean of its divisors is an integer number (2043462288).

Almost surely, 2^21012121212 is an apocalyptic number.

It is an amenable number.

21012121212 is an abundant number, since it is smaller than the sum of its proper divisors (28030973700).

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

21012121212 is a wasteful number, since it uses less digits than its factorization.

21012121212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 529009 (or 529007 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21012121212 its reverse (21212121012), we get a palindrome (42224242224).

The spelling of 21012121212 in words is "twenty-one billion, twelve million, one hundred twenty-one thousand, two hundred twelve".