21354121231 has 2 divisors, whose sum is σ = 21354121232. Its totient is φ = 21354121230.

The previous prime is 21354121213. The next prime is 21354121259. The reversal of 21354121231 is 13212145312.

Together with previous prime (21354121213) it forms an Ormiston pair, because they use the same digits, order apart.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21354121231 - 2⁹ = 21354120719 is a prime.

It is a super-2 number, since 2×21354121231² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21354121196 and 21354121205.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21354121211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10677060615 + 10677060616.

It is an arithmetic number, because the mean of its divisors is an integer number (10677060616).

Almost surely, 2^21354121231 is an apocalyptic number.

21354121231 is a deficient number, since it is larger than the sum of its proper divisors (1).

21354121231 is an equidigital number, since it uses as much as digits as its factorization.

21354121231 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1440, while the sum is 25.

Adding to 21354121231 its reverse (13212145312), we get a palindrome (34566266543).

The spelling of 21354121231 in words is "twenty-one billion, three hundred fifty-four million, one hundred twenty-one thousand, two hundred thirty-one".