51240031 has 4 divisors (see below), whose sum is σ = 51283152. Its totient is φ = 51196912.

The previous prime is 51240019. The next prime is 51240073. The reversal of 51240031 is 13004215.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 51240031 - 2⁹ = 51239519 is a prime.

It is a super-2 number, since 2×51240031² = 5251081553761922, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 51239987 and 51240014.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51240001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 19726 + ... + 22171.

It is an arithmetic number, because the mean of its divisors is an integer number (12820788).

Almost surely, 2^51240031 is an apocalyptic number.

51240031 is a deficient number, since it is larger than the sum of its proper divisors (43121).

51240031 is a wasteful number, since it uses less digits than its factorization.

51240031 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 43120.

The product of its (nonzero) digits is 120, while the sum is 16.

The square root of 51240031 is about 7158.2142326142. The cubic root of 51240031 is about 371.4238561884.

Adding to 51240031 its reverse (13004215), we get a palindrome (64244246).

The spelling of 51240031 in words is "fifty-one million, two hundred forty thousand, thirty-one".