216639953 has 2 divisors, whose sum is σ = 216639954. Its totient is φ = 216639952.

The previous prime is 216639937. The next prime is 216639989. The reversal of 216639953 is 359936612.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 200703889 + 15936064 = 14167^2 + 3992^2 .

It is a cyclic number.

It is not a de Polignac number, because 216639953 - 2⁴ = 216639937 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (216639923) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 108319976 + 108319977.

It is an arithmetic number, because the mean of its divisors is an integer number (108319977).

Almost surely, 2^216639953 is an apocalyptic number.

It is an amenable number.

216639953 is a deficient number, since it is larger than the sum of its proper divisors (1).

216639953 is an equidigital number, since it uses as much as digits as its factorization.

216639953 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 262440, while the sum is 44.

The square root of 216639953 is about 14718.6939977703. The cubic root of 216639953 is about 600.5919648447.

The spelling of 216639953 in words is "two hundred sixteen million, six hundred thirty-nine thousand, nine hundred fifty-three".