66661867 has 2 divisors, whose sum is σ = 66661868. Its totient is φ = 66661866.

The previous prime is 66661853. The next prime is 66661883. The reversal of 66661867 is 76816666.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66661867 - 2¹⁵ = 66629099 is a prime.

It is a super-4 number, since 4×66661867⁴ (a number of 32 digits) contains 4444 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66661817) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33330933 + 33330934.

It is an arithmetic number, because the mean of its divisors is an integer number (33330934).

Almost surely, 2^66661867 is an apocalyptic number.

66661867 is a deficient number, since it is larger than the sum of its proper divisors (1).

66661867 is an equidigital number, since it uses as much as digits as its factorization.

66661867 is an evil number, because the sum of its binary digits is even.

The product of its digits is 435456, while the sum is 46.

The square root of 66661867 is about 8164.6718856302. The cubic root of 66661867 is about 405.4704019573.

It can be divided in two parts, 66661 and 867, that added together give a triangular number (67528 = T₃₆₇).

The spelling of 66661867 in words is "sixty-six million, six hundred sixty-one thousand, eight hundred sixty-seven".