66661506 has 12 divisors (see below), whose sum is σ = 144433302. Its totient is φ = 22220496.

The previous prime is 66661489. The next prime is 66661537. The reversal of 66661506 is 60516666.

66661506 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in only one way, i.e., 47817225 + 18844281 = 6915^2 + 4341^2 .

It is a Curzon number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1851691 + ... + 1851726.

Almost surely, 2^66661506 is an apocalyptic number.

66661506 is an abundant number, since it is smaller than the sum of its proper divisors (77771796).

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

66661506 is a wasteful number, since it uses less digits than its factorization.

66661506 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3703425 (or 3703422 counting only the distinct ones).

The product of its (nonzero) digits is 38880, while the sum is 36.

The square root of 66661506 is about 8164.6497781595. The cubic root of 66661506 is about 405.4696700292.

The spelling of 66661506 in words is "sixty-six million, six hundred sixty-one thousand, five hundred six".