51151611681 has 6 divisors (see below), whose sum is σ = 73885661330. Its totient is φ = 34101074448.

The previous prime is 51151611673. The next prime is 51151611689. The reversal of 51151611681 is 18611615115.

It is a happy number.

51151611681 is a `hidden beast` number, since 51 + 1 + 516 + 1 + 16 + 81 = 666.

It is an interprime number because it is at equal distance from previous prime (51151611673) and next prime (51151611689).

It can be written as a sum of positive squares in only one way, i.e., 41426496225 + 9725115456 = 203535^2 + 98616^2 .

It is not a de Polignac number, because 51151611681 - 2³ = 51151611673 is a prime.

It is a super-2 number, since 2×51151611681² (a number of 22 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (51151611689) 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, 2841756196 + ... + 2841756213.

Almost surely, 2^51151611681 is an apocalyptic number.

It is an amenable number.

51151611681 is a deficient number, since it is larger than the sum of its proper divisors (22734049649).

51151611681 is a wasteful number, since it uses less digits than its factorization.

51151611681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5683512415 (or 5683512412 counting only the distinct ones).

The product of its digits is 7200, while the sum is 36.

The spelling of 51151611681 in words is "fifty-one billion, one hundred fifty-one million, six hundred eleven thousand, six hundred eighty-one".