21168023 has 2 divisors, whose sum is σ = 21168024. Its totient is φ = 21168022.

The previous prime is 21167989. The next prime is 21168031. The reversal of 21168023 is 32086112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21168023 - 2¹² = 21163927 is a prime.

It is a super-3 number, since 3×21168023³ (a number of 23 digits) contains 333 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21168023.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21168053) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10584011 + 10584012.

It is an arithmetic number, because the mean of its divisors is an integer number (10584012).

Almost surely, 2^21168023 is an apocalyptic number.

21168023 is a deficient number, since it is larger than the sum of its proper divisors (1).

21168023 is an equidigital number, since it uses as much as digits as its factorization.

21168023 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 576, while the sum is 23.

The square root of 21168023 is about 4600.8719825703. The cubic root of 21168023 is about 276.6262777125.

The spelling of 21168023 in words is "twenty-one million, one hundred sixty-eight thousand, twenty-three".