21748589 has 2 divisors, whose sum is σ = 21748590. Its totient is φ = 21748588.

The previous prime is 21748561. The next prime is 21748607. The reversal of 21748589 is 98584712.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19669225 + 2079364 = 4435^2 + 1442^2 .

It is a cyclic number.

It is not a de Polignac number, because 21748589 - 2⁸ = 21748333 is a prime.

It is a super-2 number, since 2×21748589² = 946002246981842, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21748549) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10874294 + 10874295.

It is an arithmetic number, because the mean of its divisors is an integer number (10874295).

Almost surely, 2^21748589 is an apocalyptic number.

It is an amenable number.

21748589 is a deficient number, since it is larger than the sum of its proper divisors (1).

21748589 is an equidigital number, since it uses as much as digits as its factorization.

21748589 is an evil number, because the sum of its binary digits is even.

The product of its digits is 161280, while the sum is 44.

The square root of 21748589 is about 4663.5382490122. The cubic root of 21748589 is about 279.1324722158.

The spelling of 21748589 in words is "twenty-one million, seven hundred forty-eight thousand, five hundred eighty-nine".