66420091 has 2 divisors, whose sum is σ = 66420092. Its totient is φ = 66420090.

The previous prime is 66420061. The next prime is 66420149. The reversal of 66420091 is 19002466.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66420091 - 2⁷ = 66419963 is a prime.

It is not a weakly prime, because it can be changed into another prime (66420061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33210045 + 33210046.

It is an arithmetic number, because the mean of its divisors is an integer number (33210046).

Almost surely, 2^66420091 is an apocalyptic number.

66420091 is a deficient number, since it is larger than the sum of its proper divisors (1).

66420091 is an equidigital number, since it uses as much as digits as its factorization.

66420091 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 2592, while the sum is 28.

The square root of 66420091 is about 8149.8522072489. The cubic root of 66420091 is about 404.9796077727.

The spelling of 66420091 in words is "sixty-six million, four hundred twenty thousand, ninety-one".