66638678 has 16 divisors (see below), whose sum is σ = 101412864. Its totient is φ = 32838120.

The previous prime is 66638647. The next prime is 66638687. The reversal of 66638678 is 87683666.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 41633 + ... + 43203.

It is an arithmetic number, because the mean of its divisors is an integer number (6338304).

Almost surely, 2^66638678 is an apocalyptic number.

66638678 is a deficient number, since it is larger than the sum of its proper divisors (34774186).

66638678 is a wasteful number, since it uses less digits than its factorization.

66638678 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1867.

The product of its digits is 1741824, while the sum is 50.

The square root of 66638678 is about 8163.2516805499. The cubic root of 66638678 is about 405.4233808540.

The spelling of 66638678 in words is "sixty-six million, six hundred thirty-eight thousand, six hundred seventy-eight".