66165908461 has 4 divisors (see below), whose sum is σ = 66171390172. Its totient is φ = 66160426752.

The previous prime is 66165908453. The next prime is 66165908507. The reversal of 66165908461 is 16480956166.

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 29601202500 + 36564705961 = 172050^2 + 191219^2 .

It is a cyclic number.

It is not a de Polignac number, because 66165908461 - 2³ = 66165908453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 66165908399 and 66165908408.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66165908401) 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, 2722710 + ... + 2746903.

It is an arithmetic number, because the mean of its divisors is an integer number (16542847543).

Almost surely, 2^66165908461 is an apocalyptic number.

It is an amenable number.

66165908461 is a deficient number, since it is larger than the sum of its proper divisors (5481711).

66165908461 is a wasteful number, since it uses less digits than its factorization.

66165908461 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5481710.

The product of its (nonzero) digits is 1866240, while the sum is 52.

The spelling of 66165908461 in words is "sixty-six billion, one hundred sixty-five million, nine hundred eight thousand, four hundred sixty-one".