20542117 has 4 divisors (see below), whose sum is σ = 20627596. Its totient is φ = 20456640.

The previous prime is 20542099. The next prime is 20542153. The reversal of 20542117 is 71124502.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14753281 + 5788836 = 3841^2 + 2406^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20542117 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20548117) by changing a digit.

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, 42378 + ... + 42859.

It is an arithmetic number, because the mean of its divisors is an integer number (5156899).

Almost surely, 2^20542117 is an apocalyptic number.

It is an amenable number.

20542117 is a deficient number, since it is larger than the sum of its proper divisors (85479).

20542117 is an equidigital number, since it uses as much as digits as its factorization.

20542117 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 85478.

The product of its (nonzero) digits is 560, while the sum is 22.

The square root of 20542117 is about 4532.3412272246. The cubic root of 20542117 is about 273.8724831544.

Adding to 20542117 its reverse (71124502), we get a palindrome (91666619).

The spelling of 20542117 in words is "twenty million, five hundred forty-two thousand, one hundred seventeen".