21423019 has 2 divisors, whose sum is σ = 21423020. Its totient is φ = 21423018.

The previous prime is 21423007. The next prime is 21423053. The reversal of 21423019 is 91032412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21423019 - 2¹⁵ = 21390251 is a prime.

It is a super-2 number, since 2×21423019² = 917891486148722, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21423079) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10711509 + 10711510.

It is an arithmetic number, because the mean of its divisors is an integer number (10711510).

Almost surely, 2^21423019 is an apocalyptic number.

21423019 is a deficient number, since it is larger than the sum of its proper divisors (1).

21423019 is an equidigital number, since it uses as much as digits as its factorization.

21423019 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 21423019 is about 4628.5007291779. The cubic root of 21423019 is about 277.7326199243.

The spelling of 21423019 in words is "twenty-one million, four hundred twenty-three thousand, nineteen".