66939787 has 2 divisors, whose sum is σ = 66939788. Its totient is φ = 66939786.

The previous prime is 66939739. The next prime is 66939791. The reversal of 66939787 is 78793966.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66939787 is a prime.

It is not a weakly prime, because it can be changed into another prime (66939487) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33469893 + 33469894.

It is an arithmetic number, because the mean of its divisors is an integer number (33469894).

Almost surely, 2^66939787 is an apocalyptic number.

66939787 is a deficient number, since it is larger than the sum of its proper divisors (1).

66939787 is an equidigital number, since it uses as much as digits as its factorization.

66939787 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3429216, while the sum is 55.

The square root of 66939787 is about 8181.6738507472. The cubic root of 66939787 is about 406.0331029332.

The spelling of 66939787 in words is "sixty-six million, nine hundred thirty-nine thousand, seven hundred eighty-seven".