66443957 has 2 divisors, whose sum is σ = 66443958. Its totient is φ = 66443956.

The previous prime is 66443891. The next prime is 66443981. The reversal of 66443957 is 75934466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 65431921 + 1012036 = 8089^2 + 1006^2 .

It is a cyclic number.

It is not a de Polignac number, because 66443957 - 2¹⁰ = 66442933 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66443357) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33221978 + 33221979.

It is an arithmetic number, because the mean of its divisors is an integer number (33221979).

Almost surely, 2^66443957 is an apocalyptic number.

It is an amenable number.

66443957 is a deficient number, since it is larger than the sum of its proper divisors (1).

66443957 is an equidigital number, since it uses as much as digits as its factorization.

66443957 is an evil number, because the sum of its binary digits is even.

The product of its digits is 544320, while the sum is 44.

The square root of 66443957 is about 8151.3162740750. The cubic root of 66443957 is about 405.0281075854.

It can be divided in two parts, 6644 and 3957, that added together give a palindrome (10601).

The spelling of 66443957 in words is "sixty-six million, four hundred forty-three thousand, nine hundred fifty-seven".