65956991 has 16 divisors (see below), whose sum is σ = 72640800. Its totient is φ = 59609088.

The previous prime is 65956973. The next prime is 65956997. The reversal of 65956991 is 19965956.

It is a cyclic number.

It is not a de Polignac number, because 65956991 - 2⁶ = 65956927 is a prime.

It is a super-3 number, since 3×65956991³ (a number of 24 digits) contains 333 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 (65956997) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 173840 + ... + 174218.

It is an arithmetic number, because the mean of its divisors is an integer number (4540050).

Almost surely, 2^65956991 is an apocalyptic number.

65956991 is a deficient number, since it is larger than the sum of its proper divisors (6683809).

65956991 is a wasteful number, since it uses less digits than its factorization.

65956991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 778.

The product of its digits is 656100, while the sum is 50.

The square root of 65956991 is about 8121.3909522938. The cubic root of 65956991 is about 404.0362003147.

The spelling of 65956991 in words is "sixty-five million, nine hundred fifty-six thousand, nine hundred ninety-one".