66661279 has 2 divisors, whose sum is σ = 66661280. Its totient is φ = 66661278.

The previous prime is 66661247. The next prime is 66661289. The reversal of 66661279 is 97216666.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66661279 - 2⁵ = 66661247 is a prime.

It is a super-2 number, since 2×66661279² = 8887452235831682, which contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66661289) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33330639 + 33330640.

It is an arithmetic number, because the mean of its divisors is an integer number (33330640).

Almost surely, 2^66661279 is an apocalyptic number.

66661279 is a deficient number, since it is larger than the sum of its proper divisors (1).

66661279 is an equidigital number, since it uses as much as digits as its factorization.

66661279 is an evil number, because the sum of its binary digits is even.

The product of its digits is 163296, while the sum is 43.

The square root of 66661279 is about 8164.6358767553. The cubic root of 66661279 is about 405.4692097850.

The spelling of 66661279 in words is "sixty-six million, six hundred sixty-one thousand, two hundred seventy-nine".