66665537 has 2 divisors, whose sum is σ = 66665538. Its totient is φ = 66665536.

The previous prime is 66665513. The next prime is 66665567. The reversal of 66665537 is 73556666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66650896 + 14641 = 8164^2 + 121^2 .

It is a cyclic number.

It is not a de Polignac number, because 66665537 - 2¹⁴ = 66649153 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66665567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33332768 + 33332769.

It is an arithmetic number, because the mean of its divisors is an integer number (33332769).

Almost surely, 2^66665537 is an apocalyptic number.

It is an amenable number.

66665537 is a deficient number, since it is larger than the sum of its proper divisors (1).

66665537 is an equidigital number, since it uses as much as digits as its factorization.

66665537 is an evil number, because the sum of its binary digits is even.

The product of its digits is 680400, while the sum is 44.

The square root of 66665537 is about 8164.8966313114. The cubic root of 66665537 is about 405.4778427383.

The spelling of 66665537 in words is "sixty-six million, six hundred sixty-five thousand, five hundred thirty-seven".