65681817445 has 4 divisors (see below), whose sum is σ = 78818180940. Its totient is φ = 52545453952.

The previous prime is 65681817413. The next prime is 65681817463. The reversal of 65681817445 is 54471818656.

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 48399560001 + 17282257444 = 219999^2 + 131462^2 .

It is a cyclic number.

It is not a de Polignac number, because 65681817445 - 2⁵ = 65681817413 is a prime.

It is a super-2 number, since 2×65681817445² (a number of 22 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6568181740 + ... + 6568181749.

It is an arithmetic number, because the mean of its divisors is an integer number (19704545235).

Almost surely, 2^65681817445 is an apocalyptic number.

It is an amenable number.

65681817445 is a deficient number, since it is larger than the sum of its proper divisors (13136363495).

65681817445 is a wasteful number, since it uses less digits than its factorization.

65681817445 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13136363494.

The product of its digits is 6451200, while the sum is 55.

The spelling of 65681817445 in words is "sixty-five billion, six hundred eighty-one million, eight hundred seventeen thousand, four hundred forty-five".