21748665427 has 4 divisors (see below), whose sum is σ = 22694259600. Its totient is φ = 20803071256.

The previous prime is 21748665413. The next prime is 21748665451. The reversal of 21748665427 is 72456684712.

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

It is a cyclic number.

It is not a de Polignac number, because 21748665427 - 2⁷ = 21748665299 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21748665227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 472797052 + ... + 472797097.

It is an arithmetic number, because the mean of its divisors is an integer number (5673564900).

Almost surely, 2^21748665427 is an apocalyptic number.

21748665427 is a deficient number, since it is larger than the sum of its proper divisors (945594173).

21748665427 is an equidigital number, since it uses as much as digits as its factorization.

21748665427 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 945594172.

The product of its digits is 4515840, while the sum is 52.

The spelling of 21748665427 in words is "twenty-one billion, seven hundred forty-eight million, six hundred sixty-five thousand, four hundred twenty-seven".