21425221317 has 4 divisors (see below), whose sum is σ = 28566961760. Its totient is φ = 14283480876.

The previous prime is 21425221297. The next prime is 21425221361. The reversal of 21425221317 is 71312252412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21425221317 - 2¹⁸ = 21424959173 is a prime.

It is a super-3 number, since 3×21425221317³ (a number of 32 digits) contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21425221417) 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, 3570870217 + ... + 3570870222.

It is an arithmetic number, because the mean of its divisors is an integer number (7141740440).

Almost surely, 2^21425221317 is an apocalyptic number.

It is an amenable number.

21425221317 is a deficient number, since it is larger than the sum of its proper divisors (7141740443).

21425221317 is an equidigital number, since it uses as much as digits as its factorization.

21425221317 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7141740442.

The product of its digits is 6720, while the sum is 30.

Adding to 21425221317 its reverse (71312252412), we get a palindrome (92737473729).

The spelling of 21425221317 in words is "twenty-one billion, four hundred twenty-five million, two hundred twenty-one thousand, three hundred seventeen".