651630 has 64 divisors (see below), whose sum is σ = 1866240. Its totient is φ = 142464.

The previous prime is 651617. The next prime is 651641. The reversal of 651630 is 36156.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 651597 and 651606.

It is a congruent number.

It is an unprimeable number.

651630 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 6037 + ... + 6143.

It is an arithmetic number, because the mean of its divisors is an integer number (29160).

2⁶⁵¹⁶³⁰ is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 651630, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (933120).

651630 is an abundant number, since it is smaller than the sum of its proper divisors (1214610).

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

651630 is a wasteful number, since it uses less digits than its factorization.

651630 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 153.

The product of its (nonzero) digits is 540, while the sum is 21.

The square root of 651630 is about 807.2360249642. The cubic root of 651630 is about 86.6962587967.

Adding to 651630 its reverse (36156), we get a palindrome (687786).

The spelling of 651630 in words is "six hundred fifty-one thousand, six hundred thirty".