51408181 has 6 divisors (see below), whose sum is σ = 56506646. Its totient is φ = 46734600.

The previous prime is 51408179. The next prime is 51408193. The reversal of 51408181 is 18180415.

It can be written as a sum of positive squares in only one way, i.e., 50339025 + 1069156 = 7095^2 + 1034^2 .

It is not a de Polignac number, because 51408181 - 2¹ = 51408179 is a prime.

It is a super-2 number, since 2×51408181² = 5285602147457522, 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 (51408121) 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, 212310 + ... + 212551.

Almost surely, 2^51408181 is an apocalyptic number.

It is an amenable number.

51408181 is a deficient number, since it is larger than the sum of its proper divisors (5098465).

51408181 is a wasteful number, since it uses less digits than its factorization.

51408181 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 424883 (or 424872 counting only the distinct ones).

The product of its (nonzero) digits is 1280, while the sum is 28.

The square root of 51408181 is about 7169.9498603547. The cubic root of 51408181 is about 371.8297024693.

Adding to 51408181 its reverse (18180415), we get a palindrome (69588596).

The spelling of 51408181 in words is "fifty-one million, four hundred eight thousand, one hundred eighty-one".