51215418 has 24 divisors (see below), whose sum is σ = 112114548. Its totient is φ = 16895232.

The previous prime is 51215377. The next prime is 51215419. The reversal of 51215418 is 81451215.

It can be written as a sum of positive squares in 2 ways, for example, as 50168889 + 1046529 = 7083^2 + 1023^2 .

It is a junction number, because it is equal to n+sod(n) for n = 51215391 and 51215400.

It is not an unprimeable number, because it can be changed into a prime (51215419) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 12921 + ... + 16412.

Almost surely, 2^51215418 is an apocalyptic number.

51215418 is an abundant number, since it is smaller than the sum of its proper divisors (60899130).

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

51215418 is a wasteful number, since it uses less digits than its factorization.

51215418 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29438 (or 29435 counting only the distinct ones).

The product of its digits is 1600, while the sum is 27.

The square root of 51215418 is about 7156.4948124064. The cubic root of 51215418 is about 371.3643758736.

The spelling of 51215418 in words is "fifty-one million, two hundred fifteen thousand, four hundred eighteen".