21489753 has 4 divisors (see below), whose sum is σ = 28653008. Its totient is φ = 14326500.

The previous prime is 21489739. The next prime is 21489761. The reversal of 21489753 is 35798412.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 21489753 - 2⁴ = 21489737 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (21489053) 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 in 3 ways as a sum of consecutive naturals, for example, 3581623 + ... + 3581628.

It is an arithmetic number, because the mean of its divisors is an integer number (7163252).

Almost surely, 2^21489753 is an apocalyptic number.

It is an amenable number.

21489753 is a deficient number, since it is larger than the sum of its proper divisors (7163255).

21489753 is an equidigital number, since it uses as much as digits as its factorization.

21489753 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7163254.

The product of its digits is 60480, while the sum is 39.

The square root of 21489753 is about 4635.7041536319. The cubic root of 21489753 is about 278.0207056331.

The spelling of 21489753 in words is "twenty-one million, four hundred eighty-nine thousand, seven hundred fifty-three".