21636037 has 2 divisors, whose sum is σ = 21636038. Its totient is φ = 21636036.

The previous prime is 21636023. The next prime is 21636049. The reversal of 21636037 is 73063612.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 14243076 + 7392961 = 3774^2 + 2719^2 .

It is a cyclic number.

It is not a de Polignac number, because 21636037 - 2¹⁹ = 21111749 is a prime.

It is a Chen prime.

It is equal to p_1367641 and since 21636037 and 1367641 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 21635996 and 21636014.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21636007) 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 as a sum of consecutive naturals, namely, 10818018 + 10818019.

It is an arithmetic number, because the mean of its divisors is an integer number (10818019).

Almost surely, 2^21636037 is an apocalyptic number.

It is an amenable number.

21636037 is a deficient number, since it is larger than the sum of its proper divisors (1).

21636037 is an equidigital number, since it uses as much as digits as its factorization.

21636037 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 4536, while the sum is 28.

The square root of 21636037 is about 4651.4553636470. The cubic root of 21636037 is about 278.6501226096.

Adding to 21636037 its reverse (73063612), we get a palindrome (94699649).

The spelling of 21636037 in words is "twenty-one million, six hundred thirty-six thousand, thirty-seven".