21212021231 has 8 divisors (see below), whose sum is σ = 21289994880. Its totient is φ = 21134178648.

The previous prime is 21212021221. The next prime is 21212021267. The reversal of 21212021231 is 13212021212.

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 21212021231 - 2²⁶ = 21144912367 is a prime.

It is a super-2 number, since 2×21212021231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21212021221) by changing a digit.

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 in 7 ways as a sum of consecutive naturals, for example, 297590 + ... + 361916.

It is an arithmetic number, because the mean of its divisors is an integer number (2661249360).

Almost surely, 2^21212021231 is an apocalyptic number.

21212021231 is a deficient number, since it is larger than the sum of its proper divisors (77973649).

21212021231 is an equidigital number, since it uses as much as digits as its factorization.

21212021231 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 65533.

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21212021231 its reverse (13212021212), we get a palindrome (34424042443).

The spelling of 21212021231 in words is "twenty-one billion, two hundred twelve million, twenty-one thousand, two hundred thirty-one".