21521345471 has 2 divisors, whose sum is σ = 21521345472. Its totient is φ = 21521345470.

The previous prime is 21521345407. The next prime is 21521345491. The reversal of 21521345471 is 17454312512.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21521345471 - 2⁶ = 21521345407 is a prime.

It is a super-3 number, since 3×21521345471³ (a number of 32 digits) contains 333 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21521345491) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10760672735 + 10760672736.

It is an arithmetic number, because the mean of its divisors is an integer number (10760672736).

Almost surely, 2^21521345471 is an apocalyptic number.

21521345471 is a deficient number, since it is larger than the sum of its proper divisors (1).

21521345471 is an equidigital number, since it uses as much as digits as its factorization.

21521345471 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 33600, while the sum is 35.

Adding to 21521345471 its reverse (17454312512), we get a palindrome (38975657983).

The spelling of 21521345471 in words is "twenty-one billion, five hundred twenty-one million, three hundred forty-five thousand, four hundred seventy-one".