21423007 has 2 divisors, whose sum is σ = 21423008. Its totient is φ = 21423006.

The previous prime is 21422993. The next prime is 21423019. The reversal of 21423007 is 70032412.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21423007 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21423067) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10711503 + 10711504.

It is an arithmetic number, because the mean of its divisors is an integer number (10711504).

Almost surely, 2^21423007 is an apocalyptic number.

21423007 is a deficient number, since it is larger than the sum of its proper divisors (1).

21423007 is an equidigital number, since it uses as much as digits as its factorization.

21423007 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 336, while the sum is 19.

The square root of 21423007 is about 4628.4994328616. The cubic root of 21423007 is about 277.7325680675.

Adding to 21423007 its reverse (70032412), we get a palindrome (91455419).

The spelling of 21423007 in words is "twenty-one million, four hundred twenty-three thousand, seven".