66406601 has 4 divisors (see below), whose sum is σ = 68201412. Its totient is φ = 64611792.

The previous prime is 66406583. The next prime is 66406603. The reversal of 66406601 is 10660466.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 59521225 + 6885376 = 7715^2 + 2624^2 .

It is a cyclic number.

It is not a de Polignac number, because 66406601 - 2⁶ = 66406537 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (66406603) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 897350 + ... + 897423.

It is an arithmetic number, because the mean of its divisors is an integer number (17050353).

Almost surely, 2^66406601 is an apocalyptic number.

It is an amenable number.

66406601 is a deficient number, since it is larger than the sum of its proper divisors (1794811).

66406601 is a wasteful number, since it uses less digits than its factorization.

66406601 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1794810.

The product of its (nonzero) digits is 5184, while the sum is 29.

The square root of 66406601 is about 8149.0245428517. The cubic root of 66406601 is about 404.9521886353.

The spelling of 66406601 in words is "sixty-six million, four hundred six thousand, six hundred one".