20021604 has 12 divisors (see below), whose sum is σ = 46717104. Its totient is φ = 6673864.

The previous prime is 20021549. The next prime is 20021623. The reversal of 20021604 is 40612002.

It is a tau number, because it is divible by the number of its divisors (12).

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 834222 + ... + 834245.

It is an arithmetic number, because the mean of its divisors is an integer number (3893092).

Almost surely, 2^20021604 is an apocalyptic number.

It is an amenable number.

20021604 is an abundant number, since it is smaller than the sum of its proper divisors (26695500).

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

20021604 is a wasteful number, since it uses less digits than its factorization.

20021604 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1668474 (or 1668472 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 15.

The square root of 20021604 is about 4474.5507037020. The cubic root of 20021604 is about 271.5394636190.

Adding to 20021604 its reverse (40612002), we get a palindrome (60633606).

The spelling of 20021604 in words is "twenty million, twenty-one thousand, six hundred four".