20305631 has 2 divisors, whose sum is σ = 20305632. Its totient is φ = 20305630.

The previous prime is 20305609. The next prime is 20305643. The reversal of 20305631 is 13650302.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 20305631 - 2⁶ = 20305567 is a prime.

It is a super-2 number, since 2×20305631² = 824637300616322, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20305601) 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, 10152815 + 10152816.

It is an arithmetic number, because the mean of its divisors is an integer number (10152816).

Almost surely, 2^20305631 is an apocalyptic number.

20305631 is a deficient number, since it is larger than the sum of its proper divisors (1).

20305631 is an equidigital number, since it uses as much as digits as its factorization.

20305631 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 540, while the sum is 20.

The square root of 20305631 is about 4506.1769827649. The cubic root of 20305631 is about 272.8174612866.

Adding to 20305631 its reverse (13650302), we get a palindrome (33955933).

The spelling of 20305631 in words is "twenty million, three hundred five thousand, six hundred thirty-one".