21408476 has 12 divisors (see below), whose sum is σ = 38673600. Its totient is φ = 10358880.

The previous prime is 21408473. The next prime is 21408479. The reversal of 21408476 is 67480412.

It is an interprime number because it is at equal distance from previous prime (21408473) and next prime (21408479).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21408473) 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, 86201 + ... + 86448.

It is an arithmetic number, because the mean of its divisors is an integer number (3222800).

Almost surely, 2^21408476 is an apocalyptic number.

It is an amenable number.

21408476 is a deficient number, since it is larger than the sum of its proper divisors (17265124).

21408476 is a wasteful number, since it uses less digits than its factorization.

21408476 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 172684 (or 172682 counting only the distinct ones).

The product of its (nonzero) digits is 10752, while the sum is 32.

The square root of 21408476 is about 4626.9294353815. The cubic root of 21408476 is about 277.6697595060.

Adding to 21408476 its reverse (67480412), we get a palindrome (88888888).

The spelling of 21408476 in words is "twenty-one million, four hundred eight thousand, four hundred seventy-six".