21303123 has 16 divisors (see below), whose sum is σ = 30038400. Its totient is φ = 13392000.

The previous prime is 21303109. The next prime is 21303127. The reversal of 21303123 is 32130312.

It is not a de Polignac number, because 21303123 - 2⁶ = 21303059 is a prime.

It is not an unprimeable number, because it can be changed into a prime (21303127) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 13563 + ... + 15051.

It is an arithmetic number, because the mean of its divisors is an integer number (1877400).

Almost surely, 2^21303123 is an apocalyptic number.

21303123 is a deficient number, since it is larger than the sum of its proper divisors (8735277).

21303123 is a wasteful number, since it uses less digits than its factorization.

21303123 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1762.

The product of its (nonzero) digits is 108, while the sum is 15.

The square root of 21303123 is about 4615.5306303826. The cubic root of 21303123 is about 277.2135311740.

Adding to 21303123 its reverse (32130312), we get a palindrome (53433435).

It can be divided in two parts, 2130312 and 3, that multiplied together give a palindrome (6390936).

The spelling of 21303123 in words is "twenty-one million, three hundred three thousand, one hundred twenty-three".