21335123 has 2 divisors, whose sum is σ = 21335124. Its totient is φ = 21335122.

The previous prime is 21335117. The next prime is 21335137. The reversal of 21335123 is 32153312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21335123 - 2⁴ = 21335107 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21335095 and 21335104.

It is not a weakly prime, because it can be changed into another prime (21335113) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10667561 + 10667562.

It is an arithmetic number, because the mean of its divisors is an integer number (10667562).

Almost surely, 2^21335123 is an apocalyptic number.

21335123 is a deficient number, since it is larger than the sum of its proper divisors (1).

21335123 is an equidigital number, since it uses as much as digits as its factorization.

21335123 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 540, while the sum is 20.

The square root of 21335123 is about 4618.9958865537. The cubic root of 21335123 is about 277.3522650581.

Adding to 21335123 its reverse (32153312), we get a palindrome (53488435).

The spelling of 21335123 in words is "twenty-one million, three hundred thirty-five thousand, one hundred twenty-three".