21430423 has 16 divisors (see below), whose sum is σ = 25920000. Its totient is φ = 17308512.

The previous prime is 21430403. The next prime is 21430433. The reversal of 21430423 is 32403412.

It is a cyclic number.

It is not a de Polignac number, because 21430423 - 2¹³ = 21422231 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (19).

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21430423.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21430403) 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, 35478 + ... + 36076.

It is an arithmetic number, because the mean of its divisors is an integer number (1620000).

Almost surely, 2^21430423 is an apocalyptic number.

21430423 is a deficient number, since it is larger than the sum of its proper divisors (4489577).

21430423 is a wasteful number, since it uses less digits than its factorization.

21430423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 894.

The product of its (nonzero) digits is 576, while the sum is 19.

The square root of 21430423 is about 4629.3004871147. The cubic root of 21430423 is about 277.7646119212.

Adding to 21430423 its reverse (32403412), we get a palindrome (53833835).

The spelling of 21430423 in words is "twenty-one million, four hundred thirty thousand, four hundred twenty-three".