21273423 has 8 divisors (see below), whose sum is σ = 28391808. Its totient is φ = 14168664.

The previous prime is 21273391. The next prime is 21273431. The reversal of 21273423 is 32437212.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 21273423 - 2⁵ = 21273391 is a prime.

It is a super-2 number, since 2×21273423² = 905117052273858, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21273393 and 21273402.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21273463) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1086 + ... + 6612.

It is an arithmetic number, because the mean of its divisors is an integer number (3548976).

Almost surely, 2^21273423 is an apocalyptic number.

21273423 is a deficient number, since it is larger than the sum of its proper divisors (7118385).

21273423 is a wasteful number, since it uses less digits than its factorization.

21273423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6813.

The product of its digits is 2016, while the sum is 24.

The square root of 21273423 is about 4612.3121099943. The cubic root of 21273423 is about 277.0846444219.

The spelling of 21273423 in words is "twenty-one million, two hundred seventy-three thousand, four hundred twenty-three".