66516831 has 6 divisors (see below), whose sum is σ = 96079880. Its totient is φ = 44344548.

The previous prime is 66516817. The next prime is 66516839. The reversal of 66516831 is 13861566.

It is a happy number.

66516831 is a `hidden beast` number, since 66 + 516 + 83 + 1 = 666.

It is not a de Polignac number, because 66516831 - 2⁵ = 66516799 is a prime.

It is a super-2 number, since 2×66516831² = 8848977612565122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (66516839) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 3695371 + ... + 3695388.

Almost surely, 2^66516831 is an apocalyptic number.

66516831 is a deficient number, since it is larger than the sum of its proper divisors (29563049).

66516831 is a wasteful number, since it uses less digits than its factorization.

66516831 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7390765 (or 7390762 counting only the distinct ones).

The product of its digits is 25920, while the sum is 36.

The square root of 66516831 is about 8155.7851246830. The cubic root of 66516831 is about 405.1761282403.

The spelling of 66516831 in words is "sixty-six million, five hundred sixteen thousand, eight hundred thirty-one".