21030423 has 16 divisors (see below), whose sum is σ = 29205120. Its totient is φ = 13444704.

The previous prime is 21030403. The next prime is 21030463. The reversal of 21030423 is 32403012.

It is not a de Polignac number, because 21030423 - 2¹⁰ = 21029399 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21030403) 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 15 ways as a sum of consecutive naturals, for example, 13440 + ... + 14922.

It is an arithmetic number, because the mean of its divisors is an integer number (1825320).

Almost surely, 2^21030423 is an apocalyptic number.

21030423 is a deficient number, since it is larger than the sum of its proper divisors (8174697).

21030423 is a wasteful number, since it uses less digits than its factorization.

21030423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1678.

The product of its (nonzero) digits is 144, while the sum is 15.

The square root of 21030423 is about 4585.8939150399. The cubic root of 21030423 is about 276.0255831148.

Adding to 21030423 its reverse (32403012), we get a palindrome (53433435).

The spelling of 21030423 in words is "twenty-one million, thirty thousand, four hundred twenty-three".