66689406 has 48 divisors (see below), whose sum is σ = 171260544. Its totient is φ = 19053144.

The previous prime is 66689393. The next prime is 66689417. The reversal of 66689406 is 60498666.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 6400 + ... + 13203.

It is an arithmetic number, because the mean of its divisors is an integer number (3567928).

Almost surely, 2^66689406 is an apocalyptic number.

66689406 is an abundant number, since it is smaller than the sum of its proper divisors (104571138).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

66689406 is a wasteful number, since it uses less digits than its factorization.

66689406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 19627 (or 19615 counting only the distinct ones).

The product of its (nonzero) digits is 373248, while the sum is 45.

The square root of 66689406 is about 8166.3581846500. The cubic root of 66689406 is about 405.5262295371.

The spelling of 66689406 in words is "sixty-six million, six hundred eighty-nine thousand, four hundred six".