21430123 has 8 divisors (see below), whose sum is σ = 25176816. Its totient is φ = 17983200.

The previous prime is 21430121. The next prime is 21430139. The reversal of 21430123 is 32103412.

It is a happy number.

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 21430123 - 2¹ = 21430121 is a prime.

It is an alternating number because its digits alternate between even and odd.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21430097 and 21430106.

It is not an unprimeable number, because it can be changed into a prime (21430121) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 74788 + ... + 75073.

It is an arithmetic number, because the mean of its divisors is an integer number (3147102).

Almost surely, 2^21430123 is an apocalyptic number.

21430123 is a deficient number, since it is larger than the sum of its proper divisors (3746693).

21430123 is a wasteful number, since it uses less digits than its factorization.

21430123 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 149885.

The product of its (nonzero) digits is 144, while the sum is 16.

The square root of 21430123 is about 4629.2680846976. The cubic root of 21430123 is about 277.7633157923.

Adding to 21430123 its reverse (32103412), we get a palindrome (53533535).

Subtracting 21430123 from its reverse (32103412), we obtain a square (10673289 = 3267²).

The spelling of 21430123 in words is "twenty-one million, four hundred thirty thousand, one hundred twenty-three".