66961565 has 8 divisors (see below), whose sum is σ = 87658848. Its totient is φ = 48699280.

The previous prime is 66961561. The next prime is 66961577. The reversal of 66961565 is 56516966.

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 66961565 - 2² = 66961561 is a prime.

It is a Duffinian number.

It is a plaindrome in base 3 and base 9.

It is a zygodrome in base 3.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66961561) by changing a digit.

Being equal to 14×3¹⁴-1, it is a generalized Woodall number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 608687 + ... + 608796.

It is an arithmetic number, because the mean of its divisors is an integer number (10957356).

Almost surely, 2^66961565 is an apocalyptic number.

It is an amenable number.

66961565 is a deficient number, since it is larger than the sum of its proper divisors (20697283).

66961565 is a wasteful number, since it uses less digits than its factorization.

66961565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1217499.

The product of its digits is 291600, while the sum is 44.

The square root of 66961565 is about 8183.0046437724. The cubic root of 66961565 is about 406.0771307107.

The spelling of 66961565 in words is "sixty-six million, nine hundred sixty-one thousand, five hundred sixty-five".