21073423 has 4 divisors (see below), whose sum is σ = 24083920. Its totient is φ = 18062928.

The previous prime is 21073417. The next prime is 21073447. The reversal of 21073423 is 32437012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21073423 - 2⁵ = 21073391 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21073394 and 21073403.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21073453) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1505238 + ... + 1505251.

It is an arithmetic number, because the mean of its divisors is an integer number (6020980).

Almost surely, 2^21073423 is an apocalyptic number.

21073423 is a deficient number, since it is larger than the sum of its proper divisors (3010497).

21073423 is an equidigital number, since it uses as much as digits as its factorization.

21073423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3010496.

The product of its (nonzero) digits is 1008, while the sum is 22.

The square root of 21073423 is about 4590.5798108736. The cubic root of 21073423 is about 276.2135809159.

The spelling of 21073423 in words is "twenty-one million, seventy-three thousand, four hundred twenty-three".