66631787 has 2 divisors, whose sum is σ = 66631788. Its totient is φ = 66631786.

The previous prime is 66631781. The next prime is 66631793. The reversal of 66631787 is 78713666.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (66631781) and next prime (66631793).

It is a cyclic number.

It is not a de Polignac number, because 66631787 - 2⁶ = 66631723 is a prime.

It is not a weakly prime, because it can be changed into another prime (66631781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33315893 + 33315894.

It is an arithmetic number, because the mean of its divisors is an integer number (33315894).

Almost surely, 2^66631787 is an apocalyptic number.

66631787 is a deficient number, since it is larger than the sum of its proper divisors (1).

66631787 is an equidigital number, since it uses as much as digits as its factorization.

66631787 is an evil number, because the sum of its binary digits is even.

The product of its digits is 254016, while the sum is 44.

The square root of 66631787 is about 8162.8295951833. The cubic root of 66631787 is about 405.4094056427.

The spelling of 66631787 in words is "sixty-six million, six hundred thirty-one thousand, seven hundred eighty-seven".