21423319 has 2 divisors, whose sum is σ = 21423320. Its totient is φ = 21423318.

The previous prime is 21423307. The next prime is 21423343. The reversal of 21423319 is 91332412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21423319 - 2⁵ = 21423287 is a prime.

It is a super-2 number, since 2×21423319² = 917917193951522, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21423293 and 21423302.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21423359) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10711659 + 10711660.

It is an arithmetic number, because the mean of its divisors is an integer number (10711660).

Almost surely, 2^21423319 is an apocalyptic number.

21423319 is a deficient number, since it is larger than the sum of its proper divisors (1).

21423319 is an equidigital number, since it uses as much as digits as its factorization.

21423319 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1296, while the sum is 25.

The square root of 21423319 is about 4628.5331369668. The cubic root of 21423319 is about 277.7339163398.

The spelling of 21423319 in words is "twenty-one million, four hundred twenty-three thousand, three hundred nineteen".