51138261 has 18 divisors (see below), whose sum is σ = 78471042. Its totient is φ = 32085120.

The previous prime is 51138229. The next prime is 51138271. The reversal of 51138261 is 16283115.

51138261 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 3 ways, for example, as 22043025 + 29095236 = 4695^2 + 5394^2 .

It is not a de Polignac number, because 51138261 - 2⁵ = 51138229 is a prime.

It is a super-3 number, since 3×51138261³ (a number of 24 digits) contains 333 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51138221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 7230 + ... + 12431.

Almost surely, 2^51138261 is an apocalyptic number.

51138261 is a gapful number since it is divisible by the number (51) formed by its first and last digit.

It is an amenable number.

51138261 is a deficient number, since it is larger than the sum of its proper divisors (27332781).

51138261 is a wasteful number, since it uses less digits than its factorization.

51138261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19701 (or 19681 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 51138261 is about 7151.1020828960. The cubic root of 51138261 is about 371.1777929834.

The spelling of 51138261 in words is "fifty-one million, one hundred thirty-eight thousand, two hundred sixty-one".