21748689 has 8 divisors (see below), whose sum is σ = 32220320. Its totient is φ = 14499108.

The previous prime is 21748687. The next prime is 21748693. The reversal of 21748689 is 98684712.

It is not a de Polignac number, because 21748689 - 2¹ = 21748687 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21748687) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 402727 + ... + 402780.

It is an arithmetic number, because the mean of its divisors is an integer number (4027540).

Almost surely, 2^21748689 is an apocalyptic number.

It is an amenable number.

21748689 is a deficient number, since it is larger than the sum of its proper divisors (10471631).

21748689 is an equidigital number, since it uses as much as digits as its factorization.

21748689 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 805516 (or 805510 counting only the distinct ones).

The product of its digits is 193536, while the sum is 45.

The square root of 21748689 is about 4663.5489704730. The cubic root of 21748689 is about 279.1329000322.

The spelling of 21748689 in words is "twenty-one million, seven hundred forty-eight thousand, six hundred eighty-nine".