21432004 has 18 divisors (see below), whose sum is σ = 41226542. Its totient is φ = 9741600.

The previous prime is 21431983. The next prime is 21432013. The reversal of 21432004 is 40023412.

It can be written as a sum of positive squares in only one way, i.e., 15681600 + 5750404 = 3960^2 + 2398^2 .

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 21657 + ... + 22624.

Almost surely, 2^21432004 is an apocalyptic number.

It is an amenable number.

21432004 is a deficient number, since it is larger than the sum of its proper divisors (19794538).

21432004 is a wasteful number, since it uses less digits than its factorization.

21432004 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 44307 (or 44294 counting only the distinct ones).

The product of its (nonzero) digits is 192, while the sum is 16.

The square root of 21432004 is about 4629.4712441055. The cubic root of 21432004 is about 277.7714423207.

Adding to 21432004 its reverse (40023412), we get a palindrome (61455416).

The spelling of 21432004 in words is "twenty-one million, four hundred thirty-two thousand, four".