236540021 has 2 divisors, whose sum is σ = 236540022. Its totient is φ = 236540020.

The previous prime is 236539999. The next prime is 236540071. The reversal of 236540021 is 120045632.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 228916900 + 7623121 = 15130^2 + 2761^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-236540021 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (236540071) 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, 118270010 + 118270011.

It is an arithmetic number, because the mean of its divisors is an integer number (118270011).

Almost surely, 2^236540021 is an apocalyptic number.

It is an amenable number.

236540021 is a deficient number, since it is larger than the sum of its proper divisors (1).

236540021 is an equidigital number, since it uses as much as digits as its factorization.

236540021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1440, while the sum is 23.

The square root of 236540021 is about 15379.8576391331. The cubic root of 236540021 is about 618.4456564562.

Adding to 236540021 its reverse (120045632), we get a palindrome (356585653).

The spelling of 236540021 in words is "two hundred thirty-six million, five hundred forty thousand, twenty-one".