20664538 has 8 divisors (see below), whose sum is σ = 31996800. Its totient is φ = 9998940.

The previous prime is 20664529. The next prime is 20664587. The reversal of 20664538 is 83546602.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an unprimeable number.

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, 166588 + ... + 166711.

It is an arithmetic number, because the mean of its divisors is an integer number (3999600).

Almost surely, 2^20664538 is an apocalyptic number.

20664538 is a deficient number, since it is larger than the sum of its proper divisors (11332262).

20664538 is a wasteful number, since it uses less digits than its factorization.

20664538 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 333332.

The product of its (nonzero) digits is 34560, while the sum is 34.

The square root of 20664538 is about 4545.8264375139. The cubic root of 20664538 is about 274.4154547787.

The spelling of 20664538 in words is "twenty million, six hundred sixty-four thousand, five hundred thirty-eight".