21431123 has 8 divisors (see below), whose sum is σ = 24686592. Its totient is φ = 18224136.

The previous prime is 21431119. The next prime is 21431129. The reversal of 21431123 is 32113412.

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

It is not a de Polignac number, because 21431123 - 2² = 21431119 is a prime.

It is a super-2 number, since 2×21431123² = 918586066082258, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21431129) 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 7 ways as a sum of consecutive naturals, for example, 11165 + ... + 12942.

It is an arithmetic number, because the mean of its divisors is an integer number (3085824).

Almost surely, 2^21431123 is an apocalyptic number.

21431123 is a deficient number, since it is larger than the sum of its proper divisors (3255469).

21431123 is a wasteful number, since it uses less digits than its factorization.

21431123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24241.

The product of its digits is 144, while the sum is 17.

The square root of 21431123 is about 4629.3760918724. The cubic root of 21431123 is about 277.7676361749.

Adding to 21431123 its reverse (32113412), we get a palindrome (53544535).

The spelling of 21431123 in words is "twenty-one million, four hundred thirty-one thousand, one hundred twenty-three".