66775957 has 2 divisors, whose sum is σ = 66775958. Its totient is φ = 66775956.

The previous prime is 66775939. The next prime is 66775981. The reversal of 66775957 is 75957766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 65836996 + 938961 = 8114^2 + 969^2 .

It is a cyclic number.

It is not a de Polignac number, because 66775957 - 2²³ = 58387349 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66775927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33387978 + 33387979.

It is an arithmetic number, because the mean of its divisors is an integer number (33387979).

Almost surely, 2^66775957 is an apocalyptic number.

It is an amenable number.

66775957 is a deficient number, since it is larger than the sum of its proper divisors (1).

66775957 is an equidigital number, since it uses as much as digits as its factorization.

66775957 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2778300, while the sum is 52.

The square root of 66775957 is about 8171.6557073827. The cubic root of 66775957 is about 405.7015873627.

The spelling of 66775957 in words is "sixty-six million, seven hundred seventy-five thousand, nine hundred fifty-seven".