65778641 has 4 divisors (see below), whose sum is σ = 68046900. Its totient is φ = 63510384.

The previous prime is 65778619. The next prime is 65778659. The reversal of 65778641 is 14687756.

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 32092225 + 33686416 = 5665^2 + 5804^2 .

It is a cyclic number.

It is not a de Polignac number, because 65778641 - 2¹⁰ = 65777617 is a prime.

It is a super-2 number, since 2×65778641² = 8653659223613762, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 65778592 and 65778601.

It is not an unprimeable number, because it can be changed into a prime (65778611) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1134086 + ... + 1134143.

It is an arithmetic number, because the mean of its divisors is an integer number (17011725).

Almost surely, 2^65778641 is an apocalyptic number.

It is an amenable number.

65778641 is a deficient number, since it is larger than the sum of its proper divisors (2268259).

65778641 is a wasteful number, since it uses less digits than its factorization.

65778641 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2268258.

The product of its digits is 282240, while the sum is 44.

The square root of 65778641 is about 8110.4032575452. The cubic root of 65778641 is about 403.6716955883.

The spelling of 65778641 in words is "sixty-five million, seven hundred seventy-eight thousand, six hundred forty-one".