21408076 has 12 divisors (see below), whose sum is σ = 37796472. Its totient is φ = 10609088.

The previous prime is 21408071. The next prime is 21408097. The reversal of 21408076 is 67080412.

It is not an unprimeable number, because it can be changed into a prime (21408071) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 23230 + ... + 24133.

It is an arithmetic number, because the mean of its divisors is an integer number (3149706).

Almost surely, 2^21408076 is an apocalyptic number.

It is an amenable number.

21408076 is a deficient number, since it is larger than the sum of its proper divisors (16388396).

21408076 is a wasteful number, since it uses less digits than its factorization.

21408076 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 47480 (or 47478 counting only the distinct ones).

The product of its (nonzero) digits is 2688, while the sum is 28.

The square root of 21408076 is about 4626.8862099689. The cubic root of 21408076 is about 277.6680301505.

Adding to 21408076 its reverse (67080412), we get a palindrome (88488488).

The spelling of 21408076 in words is "twenty-one million, four hundred eight thousand, seventy-six".