21212112001 has 16 divisors (see below), whose sum is σ = 21720484800. Its totient is φ = 20709374400.

The previous prime is 21212111969. The next prime is 21212112007. The reversal of 21212112001 is 10021121212.

It is a cyclic number.

It is not a de Polignac number, because 21212112001 - 2⁵ = 21212111969 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21212112007) 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, 7215990 + ... + 7218928.

It is an arithmetic number, because the mean of its divisors is an integer number (1357530300).

Almost surely, 2^21212112001 is an apocalyptic number.

It is an amenable number.

21212112001 is a deficient number, since it is larger than the sum of its proper divisors (508372799).

21212112001 is a wasteful number, since it uses less digits than its factorization.

21212112001 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3840.

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

Adding to 21212112001 its reverse (10021121212), we get a palindrome (31233233213).

It can be divided in two parts, 2121211 and 2001, that added together give a palindrome (2123212).

The spelling of 21212112001 in words is "twenty-one billion, two hundred twelve million, one hundred twelve thousand, one".