21489653 has 2 divisors, whose sum is σ = 21489654. Its totient is φ = 21489652.

The previous prime is 21489631. The next prime is 21489661. The reversal of 21489653 is 35698412.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 21464689 + 24964 = 4633^2 + 158^2 .

It is a cyclic number.

It is not a de Polignac number, because 21489653 - 2¹² = 21485557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21489623) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10744826 + 10744827.

It is an arithmetic number, because the mean of its divisors is an integer number (10744827).

Almost surely, 2^21489653 is an apocalyptic number.

It is an amenable number.

21489653 is a deficient number, since it is larger than the sum of its proper divisors (1).

21489653 is an equidigital number, since it uses as much as digits as its factorization.

21489653 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 51840, while the sum is 38.

The square root of 21489653 is about 4635.6933677714. The cubic root of 21489653 is about 278.0202743870.

The spelling of 21489653 in words is "twenty-one million, four hundred eighty-nine thousand, six hundred fifty-three".