51917220 has 96 divisors (see below), whose sum is σ = 163699200. Its totient is φ = 13658112.

The previous prime is 51917207. The next prime is 51917287. The reversal of 51917220 is 2271915.

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

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 42052 + ... + 43268.

It is an arithmetic number, because the mean of its divisors is an integer number (1705200).

Almost surely, 2^51917220 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 51917220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (81849600).

51917220 is an abundant number, since it is smaller than the sum of its proper divisors (111781980).

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

51917220 is a wasteful number, since it uses less digits than its factorization.

51917220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1314 (or 1306 counting only the distinct ones).

The product of its (nonzero) digits is 1260, while the sum is 27.

The square root of 51917220 is about 7205.3605045133. The cubic root of 51917220 is about 373.0529481338.

The spelling of 51917220 in words is "fifty-one million, nine hundred seventeen thousand, two hundred twenty".