66657906 has 48 divisors (see below), whose sum is σ = 167341824. Its totient is φ = 18781632.

The previous prime is 66657859. The next prime is 66657937. The reversal of 66657906 is 60975666.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

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, 5575 + ... + 12821.

It is an arithmetic number, because the mean of its divisors is an integer number (3486288).

Almost surely, 2^66657906 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 66657906, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (83670912).

66657906 is an abundant number, since it is smaller than the sum of its proper divisors (100683918).

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

66657906 is a wasteful number, since it uses less digits than its factorization.

66657906 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7335 (or 7332 counting only the distinct ones).

The product of its (nonzero) digits is 408240, while the sum is 45.

The square root of 66657906 is about 8164.4293125729. The cubic root of 66657906 is about 405.4623708787.

The spelling of 66657906 in words is "sixty-six million, six hundred fifty-seven thousand, nine hundred six".