66156109 has 4 divisors (see below), whose sum is σ = 66303900. Its totient is φ = 66008320.

The previous prime is 66156089. The next prime is 66156131. The reversal of 66156109 is 90165166.

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 36942084 + 29214025 = 6078^2 + 5405^2 .

It is a cyclic number.

It is not a de Polignac number, because 66156109 - 2⁹ = 66155597 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66156509) 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, 73222 + ... + 74119.

It is an arithmetic number, because the mean of its divisors is an integer number (16575975).

Almost surely, 2^66156109 is an apocalyptic number.

It is an amenable number.

66156109 is a deficient number, since it is larger than the sum of its proper divisors (147791).

66156109 is a wasteful number, since it uses less digits than its factorization.

66156109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 147790.

The product of its (nonzero) digits is 9720, while the sum is 34.

The square root of 66156109 is about 8133.6405747980. The cubic root of 66156109 is about 404.4423743811.

The spelling of 66156109 in words is "sixty-six million, one hundred fifty-six thousand, one hundred nine".