66771787 has 2 divisors, whose sum is σ = 66771788. Its totient is φ = 66771786.

The previous prime is 66771779. The next prime is 66771839. The reversal of 66771787 is 78717766.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66771787 - 2³ = 66771779 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66771787.

It is not a weakly prime, because it can be changed into another prime (66774787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33385893 + 33385894.

It is an arithmetic number, because the mean of its divisors is an integer number (33385894).

Almost surely, 2^66771787 is an apocalyptic number.

66771787 is a deficient number, since it is larger than the sum of its proper divisors (1).

66771787 is an equidigital number, since it uses as much as digits as its factorization.

66771787 is an evil number, because the sum of its binary digits is even.

The product of its digits is 691488, while the sum is 49.

The square root of 66771787 is about 8171.4005531488. The cubic root of 66771787 is about 405.6931421532.

It can be divided in two parts, 6677 and 1787, that added together give a square (8464 = 92²).

The spelling of 66771787 in words is "sixty-six million, seven hundred seventy-one thousand, seven hundred eighty-seven".