21489803 has 2 divisors, whose sum is σ = 21489804. Its totient is φ = 21489802.

The previous prime is 21489799. The next prime is 21489821. The reversal of 21489803 is 30898412.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21489803 - 2² = 21489799 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21489833) 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, 10744901 + 10744902.

It is an arithmetic number, because the mean of its divisors is an integer number (10744902).

Almost surely, 2^21489803 is an apocalyptic number.

21489803 is a deficient number, since it is larger than the sum of its proper divisors (1).

21489803 is an equidigital number, since it uses as much as digits as its factorization.

21489803 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 13824, while the sum is 35.

The square root of 21489803 is about 4635.7095465527. The cubic root of 21489803 is about 278.0209212556.

The spelling of 21489803 in words is "twenty-one million, four hundred eighty-nine thousand, eight hundred three".