21420214405 has 4 divisors (see below), whose sum is σ = 25704257292. Its totient is φ = 17136171520.

The previous prime is 21420214399. The next prime is 21420214411. The reversal of 21420214405 is 50441202412.

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

It is an interprime number because it is at equal distance from previous prime (21420214399) and next prime (21420214411).

It can be written as a sum of positive squares in 2 ways, for example, as 6477352324 + 14942862081 = 80482^2 + 122241^2 .

It is a de Polignac number, because none of the positive numbers 2^k-21420214405 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 21420214405.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 2142021436 + ... + 2142021445.

It is an arithmetic number, because the mean of its divisors is an integer number (6426064323).

Almost surely, 2^21420214405 is an apocalyptic number.

It is an amenable number.

21420214405 is a deficient number, since it is larger than the sum of its proper divisors (4284042887).

21420214405 is an equidigital number, since it uses as much as digits as its factorization.

21420214405 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4284042886.

The product of its (nonzero) digits is 2560, while the sum is 25.

Adding to 21420214405 its reverse (50441202412), we get a palindrome (71861416817).

The spelling of 21420214405 in words is "twenty-one billion, four hundred twenty million, two hundred fourteen thousand, four hundred five".