66508778 has 48 divisors (see below), whose sum is σ = 127552320. Its totient is φ = 25812864.

The previous prime is 66508763. The next prime is 66508789. The reversal of 66508778 is 87780566.

66508778 is a modest number, since divided by 8778 gives 6650 as remainder.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 42050 + ... + 43602.

It is an arithmetic number, because the mean of its divisors is an integer number (2657340).

Almost surely, 2^66508778 is an apocalyptic number.

66508778 is a deficient number, since it is larger than the sum of its proper divisors (61043542).

66508778 is a wasteful number, since it uses less digits than its factorization.

66508778 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1611 (or 1604 counting only the distinct ones).

The product of its (nonzero) digits is 564480, while the sum is 47.

The square root of 66508778 is about 8155.2914111024. The cubic root of 66508778 is about 405.1597764137.

The spelling of 66508778 in words is "sixty-six million, five hundred eight thousand, seven hundred seventy-eight".