20521208 has 8 divisors (see below), whose sum is σ = 38477280. Its totient is φ = 10260600.

The previous prime is 20521181. The next prime is 20521217. The reversal of 20521208 is 80212502.

It is a tau number, because it is divible by the number of its divisors (8).

It is a super-2 number, since 2×20521208² = 842239955558528, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 20521208.

It is a congruent number.

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 as a sum of consecutive naturals, namely, 1282568 + ... + 1282583.

It is an arithmetic number, because the mean of its divisors is an integer number (4809660).

Almost surely, 2^20521208 is an apocalyptic number.

It is an amenable number.

20521208 is a deficient number, since it is larger than the sum of its proper divisors (17956072).

20521208 is a wasteful number, since it uses less digits than its factorization.

20521208 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2565157 (or 2565153 counting only the distinct ones).

The product of its (nonzero) digits is 320, while the sum is 20.

The square root of 20521208 is about 4530.0339954574. The cubic root of 20521208 is about 273.7795303242.

The spelling of 20521208 in words is "twenty million, five hundred twenty-one thousand, two hundred eight".