21423079 has 2 divisors, whose sum is σ = 21423080. Its totient is φ = 21423078.

The previous prime is 21423067. The next prime is 21423107. The reversal of 21423079 is 97032412.

It is an a-pointer prime, because the next prime (21423107) can be obtained adding 21423079 to its sum of digits (28).

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21423079 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21423019) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10711539 + 10711540.

It is an arithmetic number, because the mean of its divisors is an integer number (10711540).

Almost surely, 2^21423079 is an apocalyptic number.

21423079 is a deficient number, since it is larger than the sum of its proper divisors (1).

21423079 is an equidigital number, since it uses as much as digits as its factorization.

21423079 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3024, while the sum is 28.

The square root of 21423079 is about 4628.5072107538. The cubic root of 21423079 is about 277.7328792084.

The spelling of 21423079 in words is "twenty-one million, four hundred twenty-three thousand, seventy-nine".