21408484 has 6 divisors (see below), whose sum is σ = 37464854. Its totient is φ = 10704240.

The previous prime is 21408479. The next prime is 21408493. The reversal of 21408484 is 48480412.

It can be written as a sum of positive squares in only one way, i.e., 17040384 + 4368100 = 4128^2 + 2090^2 .

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2676057 + ... + 2676064.

Almost surely, 2^21408484 is an apocalyptic number.

It is an amenable number.

21408484 is a deficient number, since it is larger than the sum of its proper divisors (16056370).

21408484 is a wasteful number, since it uses less digits than its factorization.

21408484 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5352125 (or 5352123 counting only the distinct ones).

The product of its (nonzero) digits is 8192, while the sum is 31.

The square root of 21408484 is about 4626.9302998857. The cubic root of 21408484 is about 277.6697940929.

Adding to 21408484 its reverse (48480412), we get a palindrome (69888896).

The spelling of 21408484 in words is "twenty-one million, four hundred eight thousand, four hundred eighty-four".