51017220 has 72 divisors (see below), whose sum is σ = 161493696. Its totient is φ = 13012032.

The previous prime is 51017189. The next prime is 51017233. The reversal of 51017220 is 2271015.

It is a Harshad number since it is a multiple of its sum of digits (18).

It is a junction number, because it is equal to n+sod(n) for n = 51017193 and 51017202.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 2022 + ... + 10301.

It is an arithmetic number, because the mean of its divisors is an integer number (2242968).

Almost surely, 2^51017220 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 51017220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (80746848).

51017220 is an abundant number, since it is smaller than the sum of its proper divisors (110476476).

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

51017220 is a wasteful number, since it uses less digits than its factorization.

51017220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12361 (or 12356 counting only the distinct ones).

The product of its (nonzero) digits is 140, while the sum is 18.

The square root of 51017220 is about 7142.6339679421. The cubic root of 51017220 is about 370.8847102434.

Adding to 51017220 its reverse (2271015), we get a palindrome (53288235).

It can be divided in two parts, 5101 and 7220, that added together give a palindrome (12321).

The spelling of 51017220 in words is "fifty-one million, seventeen thousand, two hundred twenty".