66611985 has 32 divisors (see below), whose sum is σ = 120286080. Its totient is φ = 31180800.

The previous prime is 66611977. The next prime is 66612011. The reversal of 66611985 is 58911666.

It is a happy number.

It is not a de Polignac number, because 66611985 - 2³ = 66611977 is a prime.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 2176 + ... + 11745.

It is an arithmetic number, because the mean of its divisors is an integer number (3758940).

Almost surely, 2^66611985 is an apocalyptic number.

It is an amenable number.

66611985 is a deficient number, since it is larger than the sum of its proper divisors (53674095).

66611985 is a wasteful number, since it uses less digits than its factorization.

66611985 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13969.

The product of its digits is 77760, while the sum is 42.

The square root of 66611985 is about 8161.6165678130. The cubic root of 66611985 is about 405.3692410665.

It can be divided in two parts, 6661 and 1985, that added together give a triangular number (8646 = T₁₃₁).

The spelling of 66611985 in words is "sixty-six million, six hundred eleven thousand, nine hundred eighty-five".