20631137 has 2 divisors, whose sum is σ = 20631138. Its totient is φ = 20631136.

The previous prime is 20631119. The next prime is 20631139. The reversal of 20631137 is 73113602.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 17230801 + 3400336 = 4151^2 + 1844^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20631137 is a prime.

Together with 20631139, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (20631139) 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 as a sum of consecutive naturals, namely, 10315568 + 10315569.

It is an arithmetic number, because the mean of its divisors is an integer number (10315569).

Almost surely, 2^20631137 is an apocalyptic number.

It is an amenable number.

20631137 is a deficient number, since it is larger than the sum of its proper divisors (1).

20631137 is an equidigital number, since it uses as much as digits as its factorization.

20631137 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 756, while the sum is 23.

The square root of 20631137 is about 4542.1511423553. The cubic root of 20631137 is about 274.2675251326.

Adding to 20631137 its reverse (73113602), we get a palindrome (93744739).

The spelling of 20631137 in words is "twenty million, six hundred thirty-one thousand, one hundred thirty-seven".