51217218 has 32 divisors (see below), whose sum is σ = 122572800. Its totient is φ = 15758928.

The previous prime is 51217211. The next prime is 51217259. The reversal of 51217218 is 81271215.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a junction number, because it is equal to n+sod(n) for n = 51217191 and 51217200.

It is not an unprimeable number, because it can be changed into a prime (51217211) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 35778 + ... + 37181.

It is an arithmetic number, because the mean of its divisors is an integer number (3830400).

Almost surely, 2^51217218 is an apocalyptic number.

51217218 is an abundant number, since it is smaller than the sum of its proper divisors (71355582).

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

51217218 is a wasteful number, since it uses less digits than its factorization.

51217218 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 72983 (or 72977 counting only the distinct ones).

The product of its digits is 1120, while the sum is 27.

The square root of 51217218 is about 7156.6205711914. The cubic root of 51217218 is about 371.3687264388.

The spelling of 51217218 in words is "fifty-one million, two hundred seventeen thousand, two hundred eighteen".