20521117 has 4 divisors (see below), whose sum is σ = 20535840. Its totient is φ = 20506396.

The previous prime is 20521099. The next prime is 20521147. The reversal of 20521117 is 71112502.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20521117 is a prime.

It is a super-2 number, since 2×20521117² = 842232485855378, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 20521094 and 20521103.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20521147) by changing a digit.

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 3 ways as a sum of consecutive naturals, for example, 5023 + ... + 8140.

It is an arithmetic number, because the mean of its divisors is an integer number (5133960).

Almost surely, 2^20521117 is an apocalyptic number.

It is an amenable number.

20521117 is a deficient number, since it is larger than the sum of its proper divisors (14723).

20521117 is a wasteful number, since it uses less digits than its factorization.

20521117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 14722.

The product of its (nonzero) digits is 140, while the sum is 19.

The square root of 20521117 is about 4530.0239513716. The cubic root of 20521117 is about 273.7791256376.

Adding to 20521117 its reverse (71112502), we get a palindrome (91633619).

The spelling of 20521117 in words is "twenty million, five hundred twenty-one thousand, one hundred seventeen".