21734989 has 2 divisors, whose sum is σ = 21734990. Its totient is φ = 21734988.

The previous prime is 21734981. The next prime is 21735011. The reversal of 21734989 is 98943712.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 21696964 + 38025 = 4658^2 + 195^2 .

It is a cyclic number.

It is not a de Polignac number, because 21734989 - 2³ = 21734981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21734981) 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 as a sum of consecutive naturals, namely, 10867494 + 10867495.

It is an arithmetic number, because the mean of its divisors is an integer number (10867495).

Almost surely, 2^21734989 is an apocalyptic number.

It is an amenable number.

21734989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21734989 is an equidigital number, since it uses as much as digits as its factorization.

21734989 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 108864, while the sum is 43.

The square root of 21734989 is about 4662.0799006452. The cubic root of 21734989 is about 279.0742769740.

The spelling of 21734989 in words is "twenty-one million, seven hundred thirty-four thousand, nine hundred eighty-nine".