21420012423 has 8 divisors (see below), whose sum is σ = 28566215536. Its totient is φ = 14276908800.

The previous prime is 21420012377. The next prime is 21420012457. The reversal of 21420012423 is 32421002412.

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

It is not a de Polignac number, because 21420012423 - 2¹³ = 21420004231 is a prime.

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 21420012423.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21420013423) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 758698 + ... + 786423.

It is an arithmetic number, because the mean of its divisors is an integer number (3570776942).

Almost surely, 2^21420012423 is an apocalyptic number.

21420012423 is a deficient number, since it is larger than the sum of its proper divisors (7146203113).

21420012423 is a wasteful number, since it uses less digits than its factorization.

21420012423 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1549745.

The product of its (nonzero) digits is 768, while the sum is 21.

Adding to 21420012423 its reverse (32421002412), we get a palindrome (53841014835).

The spelling of 21420012423 in words is "twenty-one billion, four hundred twenty million, twelve thousand, four hundred twenty-three".