66071557 has 2 divisors, whose sum is σ = 66071558. Its totient is φ = 66071556.

The previous prime is 66071543. The next prime is 66071573. The reversal of 66071557 is 75517066.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 51926436 + 14145121 = 7206^2 + 3761^2 .

It is a cyclic number.

It is not a de Polignac number, because 66071557 - 2⁷ = 66071429 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66071507) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33035778 + 33035779.

It is an arithmetic number, because the mean of its divisors is an integer number (33035779).

Almost surely, 2^66071557 is an apocalyptic number.

It is an amenable number.

66071557 is a deficient number, since it is larger than the sum of its proper divisors (1).

66071557 is an equidigital number, since it uses as much as digits as its factorization.

66071557 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 44100, while the sum is 37.

The square root of 66071557 is about 8128.4412404839. The cubic root of 66071557 is about 404.2699993178.

The spelling of 66071557 in words is "sixty-six million, seventy-one thousand, five hundred fifty-seven".