21050134421 has 4 divisors (see below), whose sum is σ = 21053761452. Its totient is φ = 21046507392.

The previous prime is 21050134367. The next prime is 21050134423. The reversal of 21050134421 is 12443105012.

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

It can be written as a sum of positive squares in 2 ways, for example, as 8681580625 + 12368553796 = 93175^2 + 111214^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21050134421 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 (21050134423) 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, 1804796 + ... + 1816421.

It is an arithmetic number, because the mean of its divisors is an integer number (5263440363).

Almost surely, 2^21050134421 is an apocalyptic number.

It is an amenable number.

21050134421 is a deficient number, since it is larger than the sum of its proper divisors (3627031).

21050134421 is an equidigital number, since it uses as much as digits as its factorization.

21050134421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3627030.

The product of its (nonzero) digits is 960, while the sum is 23.

Adding to 21050134421 its reverse (12443105012), we get a palindrome (33493239433).

The spelling of 21050134421 in words is "twenty-one billion, fifty million, one hundred thirty-four thousand, four hundred twenty-one".