21711647481 has 4 divisors (see below), whose sum is σ = 28948863312. Its totient is φ = 14474431652.

The previous prime is 21711647443. The next prime is 21711647483. The reversal of 21711647481 is 18474611712.

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 a cyclic number.

It is not a de Polignac number, because 21711647481 - 2¹³ = 21711639289 is a prime.

It is a super-2 number, since 2×21711647481² (a number of 21 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (21711647483) 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 in 3 ways as a sum of consecutive naturals, for example, 3618607911 + ... + 3618607916.

It is an arithmetic number, because the mean of its divisors is an integer number (7237215828).

Almost surely, 2^21711647481 is an apocalyptic number.

It is an amenable number.

21711647481 is a deficient number, since it is larger than the sum of its proper divisors (7237215831).

21711647481 is an equidigital number, since it uses as much as digits as its factorization.

21711647481 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7237215830.

The product of its digits is 75264, while the sum is 42.

The spelling of 21711647481 in words is "twenty-one billion, seven hundred eleven million, six hundred forty-seven thousand, four hundred eighty-one".