20163551 has 2 divisors, whose sum is σ = 20163552. Its totient is φ = 20163550.

The previous prime is 20163529. The next prime is 20163593. The reversal of 20163551 is 15536102.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20163551 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20163151) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10081775 + 10081776.

It is an arithmetic number, because the mean of its divisors is an integer number (10081776).

Almost surely, 2^20163551 is an apocalyptic number.

20163551 is a deficient number, since it is larger than the sum of its proper divisors (1).

20163551 is an equidigital number, since it uses as much as digits as its factorization.

20163551 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 900, while the sum is 23.

The square root of 20163551 is about 4490.3842819964. The cubic root of 20163551 is about 272.1796634163.

Adding to 20163551 its reverse (15536102), we get a palindrome (35699653).

The spelling of 20163551 in words is "twenty million, one hundred sixty-three thousand, five hundred fifty-one".