66655801 has 2 divisors, whose sum is σ = 66655802. Its totient is φ = 66655800.

The previous prime is 66655751. The next prime is 66655807. The reversal of 66655801 is 10855666.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 61638201 + 5017600 = 7851^2 + 2240^2 .

It is a cyclic number.

It is not a de Polignac number, because 66655801 - 2¹⁵ = 66623033 is a prime.

It is a super-3 number, since 3×66655801³ (a number of 24 digits) contains 333 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66655807) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33327900 + 33327901.

It is an arithmetic number, because the mean of its divisors is an integer number (33327901).

Almost surely, 2^66655801 is an apocalyptic number.

It is an amenable number.

66655801 is a deficient number, since it is larger than the sum of its proper divisors (1).

66655801 is an equidigital number, since it uses as much as digits as its factorization.

66655801 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 43200, while the sum is 37.

The square root of 66655801 is about 8164.3003986870. The cubic root of 66655801 is about 405.4581027815.

The spelling of 66655801 in words is "sixty-six million, six hundred fifty-five thousand, eight hundred one".