65181381351561 has 64 divisors (see below), whose sum is σ = 107349677395200. Its totient is φ = 38898470274048.

The previous prime is 65181381351551. The next prime is 65181381351563. The reversal of 65181381351561 is 16515318318156.

65181381351561 is a `hidden beast` number, since 6 + 5 + 1 + 8 + 13 + 8 + 13 + 51 + 561 = 666.

It is not a de Polignac number, because 65181381351561 - 2²² = 65181377157257 is a prime.

It is a super-2 number, since 2×65181381351561² (a number of 28 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 65181381351498 and 65181381351507.

It is not an unprimeable number, because it can be changed into a prime (65181381351563) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 35651490 + ... + 37435163.

It is an arithmetic number, because the mean of its divisors is an integer number (1677338709300).

Almost surely, 2^{65181381351561} is an apocalyptic number.

It is an amenable number.

65181381351561 is a deficient number, since it is larger than the sum of its proper divisors (42168296043639).

65181381351561 is a wasteful number, since it uses less digits than its factorization.

65181381351561 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 73086775 (or 73086769 counting only the distinct ones).

The product of its digits is 2592000, while the sum is 54.

The spelling of 65181381351561 in words is "sixty-five trillion, one hundred eighty-one billion, three hundred eighty-one million, three hundred fifty-one thousand, five hundred sixty-one".