21423008 has 24 divisors (see below), whose sum is σ = 42309540. Its totient is φ = 10677760.

The previous prime is 21423007. The next prime is 21423019. The reversal of 21423008 is 80032412.

It can be written as a sum of positive squares in 2 ways, for example, as 21418384 + 4624 = 4628^2 + 68^2 .

It is not an unprimeable number, because it can be changed into a prime (21423007) 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, 11588 + ... + 13308.

Almost surely, 2^21423008 is an apocalyptic number.

It is an amenable number.

21423008 is a deficient number, since it is larger than the sum of its proper divisors (20886532).

21423008 is a wasteful number, since it uses less digits than its factorization.

21423008 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2120 (or 2112 counting only the distinct ones).

The product of its (nonzero) digits is 384, while the sum is 20.

The square root of 21423008 is about 4628.4995408880. The cubic root of 21423008 is about 277.7325723889.

The spelling of 21423008 in words is "twenty-one million, four hundred twenty-three thousand, eight".