51706381 has 4 divisors (see below), whose sum is σ = 51853212. Its totient is φ = 51559552.

The previous prime is 51706337. The next prime is 51706397. The reversal of 51706381 is 18360715.

51706381 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 18360715 = 5 ⋅3672143.

It can be written as a sum of positive squares in 2 ways, for example, as 30858025 + 20848356 = 5555^2 + 4566^2 .

It is a cyclic number.

It is not a de Polignac number, because 51706381 - 2²⁵ = 18151949 is a prime.

It is a super-2 number, since 2×51706381² = 5347099672234322, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51706321) 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 3 ways as a sum of consecutive naturals, for example, 72886 + ... + 73591.

It is an arithmetic number, because the mean of its divisors is an integer number (12963303).

Almost surely, 2^51706381 is an apocalyptic number.

It is an amenable number.

51706381 is a deficient number, since it is larger than the sum of its proper divisors (146831).

51706381 is a wasteful number, since it uses less digits than its factorization.

51706381 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 146830.

The product of its (nonzero) digits is 5040, while the sum is 31.

The square root of 51706381 is about 7190.7149157785. The cubic root of 51706381 is about 372.5472660470.

The spelling of 51706381 in words is "fifty-one million, seven hundred six thousand, three hundred eighty-one".