21423679 has 2 divisors, whose sum is σ = 21423680. Its totient is φ = 21423678.

The previous prime is 21423673. The next prime is 21423709. The reversal of 21423679 is 97632412.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21423679 - 2⁹ = 21423167 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21423673) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10711839 + 10711840.

It is an arithmetic number, because the mean of its divisors is an integer number (10711840).

Almost surely, 2^21423679 is an apocalyptic number.

21423679 is a deficient number, since it is larger than the sum of its proper divisors (1).

21423679 is an equidigital number, since it uses as much as digits as its factorization.

21423679 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18144, while the sum is 34.

The square root of 21423679 is about 4628.5720260141. The cubic root of 21423679 is about 277.7354720223.

The spelling of 21423679 in words is "twenty-one million, four hundred twenty-three thousand, six hundred seventy-nine".