21080004 has 24 divisors (see below), whose sum is σ = 53658528. Its totient is φ = 6387840.

The previous prime is 21079999. The next prime is 21080021. The reversal of 21080004 is 40008012.

It is an unprimeable number.

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 7 ways as a sum of consecutive naturals, for example, 79717 + ... + 79980.

It is an arithmetic number, because the mean of its divisors is an integer number (2235772).

Almost surely, 2^21080004 is an apocalyptic number.

It is an amenable number.

21080004 is an abundant number, since it is smaller than the sum of its proper divisors (32578524).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21080004 is a wasteful number, since it uses less digits than its factorization.

21080004 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 159715 (or 159713 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 15.

The square root of 21080004 is about 4591.2965489064. The cubic root of 21080004 is about 276.2423307522.

Adding to 21080004 its reverse (40008012), we get a palindrome (61088016).

The spelling of 21080004 in words is "twenty-one million, eighty thousand, four".