66640253 has 2 divisors, whose sum is σ = 66640254. Its totient is φ = 66640252.

The previous prime is 66640237. The next prime is 66640267. The reversal of 66640253 is 35204666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 43388569 + 23251684 = 6587^2 + 4822^2 .

It is a cyclic number.

It is not a de Polignac number, because 66640253 - 2⁴ = 66640237 is a prime.

It is a congruent number.

It is a weakly prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33320126 + 33320127.

It is an arithmetic number, because the mean of its divisors is an integer number (33320127).

Almost surely, 2^66640253 is an apocalyptic number.

It is an amenable number.

66640253 is a deficient number, since it is larger than the sum of its proper divisors (1).

66640253 is an equidigital number, since it uses as much as digits as its factorization.

66640253 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 25920, while the sum is 32.

The square root of 66640253 is about 8163.3481488909. The cubic root of 66640253 is about 405.4265748789.

The spelling of 66640253 in words is "sixty-six million, six hundred forty thousand, two hundred fifty-three".