236440021 has 2 divisors, whose sum is σ = 236440022. Its totient is φ = 236440020.

The previous prime is 236440019. The next prime is 236440051. The reversal of 236440021 is 120044632.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 195300625 + 41139396 = 13975^2 + 6414^2 .

It is a cyclic number.

It is not a de Polignac number, because 236440021 - 2¹ = 236440019 is a prime.

Together with 236440019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 236439974 and 236440001.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (236440051) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 118220010 + 118220011.

It is an arithmetic number, because the mean of its divisors is an integer number (118220011).

Almost surely, 2^236440021 is an apocalyptic number.

It is an amenable number.

236440021 is a deficient number, since it is larger than the sum of its proper divisors (1).

236440021 is an equidigital number, since it uses as much as digits as its factorization.

236440021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1152, while the sum is 22.

The square root of 236440021 is about 15376.6062900758. The cubic root of 236440021 is about 618.3584925130.

Adding to 236440021 its reverse (120044632), we get a palindrome (356484653).

The spelling of 236440021 in words is "two hundred thirty-six million, four hundred forty thousand, twenty-one".