66655669 has 2 divisors, whose sum is σ = 66655670. Its totient is φ = 66655668.

The previous prime is 66655661. The next prime is 66655681. The reversal of 66655669 is 96655666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 62615569 + 4040100 = 7913^2 + 2010^2 .

It is a cyclic number.

It is not a de Polignac number, because 66655669 - 2³ = 66655661 is a prime.

It is a super-2 number, since 2×66655669² = 8885956419675122, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66655661) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33327834 + 33327835.

It is an arithmetic number, because the mean of its divisors is an integer number (33327835).

Almost surely, 2^66655669 is an apocalyptic number.

It is an amenable number.

66655669 is a deficient number, since it is larger than the sum of its proper divisors (1).

66655669 is an equidigital number, since it uses as much as digits as its factorization.

66655669 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1749600, while the sum is 49.

The square root of 66655669 is about 8164.2923147080. The cubic root of 66655669 is about 405.4578351353.

The spelling of 66655669 in words is "sixty-six million, six hundred fifty-five thousand, six hundred sixty-nine".