21121212011 has 8 divisors (see below), whose sum is σ = 21826391664. Its totient is φ = 20425759200.

The previous prime is 21121211987. The next prime is 21121212019. The reversal of 21121212011 is 11021212112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21121212011 - 2¹⁰ = 21121210987 is a prime.

It is a super-2 number, since 2×21121212011² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21121212019) 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, 2427296 + ... + 2435981.

It is an arithmetic number, because the mean of its divisors is an integer number (2728298958).

Almost surely, 2^21121212011 is an apocalyptic number.

21121212011 is a deficient number, since it is larger than the sum of its proper divisors (705179653).

21121212011 is a wasteful number, since it uses less digits than its factorization.

21121212011 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4863421.

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

Adding to 21121212011 its reverse (11021212112), we get a palindrome (32142424123).

The spelling of 21121212011 in words is "twenty-one billion, one hundred twenty-one million, two hundred twelve thousand, eleven".