66366991 has 2 divisors, whose sum is σ = 66366992. Its totient is φ = 66366990.

The previous prime is 66366973. The next prime is 66367009. The reversal of 66366991 is 19966366.

It is a balanced prime because it is at equal distance from previous prime (66366973) and next prime (66367009).

It is a cyclic number.

It is not a de Polignac number, because 66366991 - 2⁵ = 66366959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66366941) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33183495 + 33183496.

It is an arithmetic number, because the mean of its divisors is an integer number (33183496).

Almost surely, 2^66366991 is an apocalyptic number.

66366991 is a deficient number, since it is larger than the sum of its proper divisors (1).

66366991 is an equidigital number, since it uses as much as digits as its factorization.

66366991 is an evil number, because the sum of its binary digits is even.

The product of its digits is 314928, while the sum is 46.

The square root of 66366991 is about 8146.5938280977. The cubic root of 66366991 is about 404.8716577533.

The spelling of 66366991 in words is "sixty-six million, three hundred sixty-six thousand, nine hundred ninety-one".