21424340233 has 2 divisors, whose sum is σ = 21424340234. Its totient is φ = 21424340232.

The previous prime is 21424340227. The next prime is 21424340243. The reversal of 21424340233 is 33204342412.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18608233744 + 2816106489 = 136412^2 + 53067^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21424340233 is a prime.

It is not a weakly prime, because it can be changed into another prime (21424340243) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10712170116 + 10712170117.

It is an arithmetic number, because the mean of its divisors is an integer number (10712170117).

Almost surely, 2^21424340233 is an apocalyptic number.

It is an amenable number.

21424340233 is a deficient number, since it is larger than the sum of its proper divisors (1).

21424340233 is an equidigital number, since it uses as much as digits as its factorization.

21424340233 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 13824, while the sum is 28.

Adding to 21424340233 its reverse (33204342412), we get a palindrome (54628682645).

The spelling of 21424340233 in words is "twenty-one billion, four hundred twenty-four million, three hundred forty thousand, two hundred thirty-three".