21425133161 has 4 divisors (see below), whose sum is σ = 22004190852. Its totient is φ = 20846075472.

The previous prime is 21425133109. The next prime is 21425133179. The reversal of 21425133161 is 16133152412.

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 13400377600 + 8024755561 = 115760^2 + 89581^2 .

It is a cyclic number.

It is not a de Polignac number, because 21425133161 - 2¹⁴ = 21425116777 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21425133101) 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, 289528790 + ... + 289528863.

It is an arithmetic number, because the mean of its divisors is an integer number (5501047713).

Almost surely, 2^21425133161 is an apocalyptic number.

It is an amenable number.

21425133161 is a deficient number, since it is larger than the sum of its proper divisors (579057691).

21425133161 is an equidigital number, since it uses as much as digits as its factorization.

21425133161 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 579057690.

The product of its digits is 4320, while the sum is 29.

Adding to 21425133161 its reverse (16133152412), we get a palindrome (37558285573).

The spelling of 21425133161 in words is "twenty-one billion, four hundred twenty-five million, one hundred thirty-three thousand, one hundred sixty-one".