51720210 has 48 divisors (see below), whose sum is σ = 137344896. Its totient is φ = 13497504.

The previous prime is 51720199. The next prime is 51720247. The reversal of 51720210 is 1202715.

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

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, 1884 + ... + 10343.

It is an arithmetic number, because the mean of its divisors is an integer number (2861352).

Almost surely, 2^51720210 is an apocalyptic number.

51720210 is an abundant number, since it is smaller than the sum of its proper divisors (85624686).

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

51720210 is a wasteful number, since it uses less digits than its factorization.

51720210 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12287 (or 12284 counting only the distinct ones).

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

The square root of 51720210 is about 7191.6764387728. The cubic root of 51720210 is about 372.5804759837.

Adding to 51720210 its reverse (1202715), we get a palindrome (52922925).

The spelling of 51720210 in words is "fifty-one million, seven hundred twenty thousand, two hundred ten".