21202321123 has 2 divisors, whose sum is σ = 21202321124. Its totient is φ = 21202321122.

The previous prime is 21202321099. The next prime is 21202321183. The reversal of 21202321123 is 32112320212.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21202321123 - 2²⁵ = 21168766691 is a prime.

It is a super-2 number, since 2×21202321123² (a number of 21 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21202321123.

It is not a weakly prime, because it can be changed into another prime (21202321183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10601160561 + 10601160562.

It is an arithmetic number, because the mean of its divisors is an integer number (10601160562).

Almost surely, 2^21202321123 is an apocalyptic number.

21202321123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21202321123 is an equidigital number, since it uses as much as digits as its factorization.

21202321123 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 19.

Adding to 21202321123 its reverse (32112320212), we get a palindrome (53314641335).

The spelling of 21202321123 in words is "twenty-one billion, two hundred two million, three hundred twenty-one thousand, one hundred twenty-three".