21265123 has 8 divisors (see below), whose sum is σ = 24419520. Its totient is φ = 18314280.

The previous prime is 21265093. The next prime is 21265129. The reversal of 21265123 is 32156212.

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

It is a cyclic number.

It is not a de Polignac number, because 21265123 - 2¹³ = 21256931 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21265094 and 21265103.

It is not an unprimeable number, because it can be changed into a prime (21265129) 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, 50665 + ... + 51082.

It is an arithmetic number, because the mean of its divisors is an integer number (3052440).

Almost surely, 2^21265123 is an apocalyptic number.

21265123 is a deficient number, since it is larger than the sum of its proper divisors (3154397).

21265123 is a wasteful number, since it uses less digits than its factorization.

21265123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 101777.

The product of its digits is 720, while the sum is 22.

The square root of 21265123 is about 4611.4122565652. The cubic root of 21265123 is about 277.0486041208.

The spelling of 21265123 in words is "twenty-one million, two hundred sixty-five thousand, one hundred twenty-three".