51918140 has 24 divisors (see below), whose sum is σ = 109356912. Its totient is φ = 20704640.

The previous prime is 51918133. The next prime is 51918143. The reversal of 51918140 is 4181915.

It is a super-2 number, since 2×51918140² = 5390986522119200, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (51918143) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 3200 + ... + 10680.

It is an arithmetic number, because the mean of its divisors is an integer number (4556538).

Almost surely, 2^51918140 is an apocalyptic number.

It is an amenable number.

51918140 is an abundant number, since it is smaller than the sum of its proper divisors (57438772).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

51918140 is a wasteful number, since it uses less digits than its factorization.

51918140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7837 (or 7835 counting only the distinct ones).

The product of its (nonzero) digits is 1440, while the sum is 29.

The square root of 51918140 is about 7205.4243455885. The cubic root of 51918140 is about 373.0551516846.

It can be divided in two parts, 5191 and 8140, that added together give a palindrome (13331).

The spelling of 51918140 in words is "fifty-one million, nine hundred eighteen thousand, one hundred forty".