21485489 has 2 divisors, whose sum is σ = 21485490. Its totient is φ = 21485488.

The previous prime is 21485437. The next prime is 21485507. The reversal of 21485489 is 98458412.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21390625 + 94864 = 4625^2 + 308^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21485489 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21485089) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10742744 + 10742745.

It is an arithmetic number, because the mean of its divisors is an integer number (10742745).

Almost surely, 2^21485489 is an apocalyptic number.

It is an amenable number.

21485489 is a deficient number, since it is larger than the sum of its proper divisors (1).

21485489 is an equidigital number, since it uses as much as digits as its factorization.

21485489 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 92160, while the sum is 41.

The square root of 21485489 is about 4635.2442222606. The cubic root of 21485489 is about 278.0023161134.

The spelling of 21485489 in words is "twenty-one million, four hundred eighty-five thousand, four hundred eighty-nine".