21004258423 has 4 divisors (see below), whose sum is σ = 21028100688. Its totient is φ = 20980416160.

The previous prime is 21004258369. The next prime is 21004258433. The reversal of 21004258423 is 32485240012.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21004258423 - 2²⁹ = 20467387511 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21004258433) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 11919811 + ... + 11921572.

It is an arithmetic number, because the mean of its divisors is an integer number (5257025172).

Almost surely, 2^21004258423 is an apocalyptic number.

21004258423 is a deficient number, since it is larger than the sum of its proper divisors (23842265).

21004258423 is an equidigital number, since it uses as much as digits as its factorization.

21004258423 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 23842264.

The product of its (nonzero) digits is 15360, while the sum is 31.

Adding to 21004258423 its reverse (32485240012), we get a palindrome (53489498435).

The spelling of 21004258423 in words is "twenty-one billion, four million, two hundred fifty-eight thousand, four hundred twenty-three".