51147681 has 24 divisors (see below), whose sum is σ = 74839680. Its totient is φ = 31052736.

The previous prime is 51147661. The next prime is 51147697. The reversal of 51147681 is 18674115.

It is a happy number.

It is not a de Polignac number, because 51147681 - 2⁷ = 51147553 is a prime.

It is a super-2 number, since 2×51147681² = 5232170543355522, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (51147661) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 39415 + ... + 40691.

It is an arithmetic number, because the mean of its divisors is an integer number (3118320).

Almost surely, 2^51147681 is an apocalyptic number.

It is an amenable number.

51147681 is a deficient number, since it is larger than the sum of its proper divisors (23691999).

51147681 is a wasteful number, since it uses less digits than its factorization.

51147681 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1385 (or 1372 counting only the distinct ones).

The product of its digits is 6720, while the sum is 33.

The square root of 51147681 is about 7151.7606923051. The cubic root of 51147681 is about 371.2005827046.

The spelling of 51147681 in words is "fifty-one million, one hundred forty-seven thousand, six hundred eighty-one".