651820 has 48 divisors (see below), whose sum is σ = 1552320. Its totient is φ = 228096.

The previous prime is 651811. The next prime is 651821. The reversal of 651820 is 28156.

It is a happy number.

651820 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a junction number, because it is equal to n+sod(n) for n = 651791 and 651800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (651821) 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, 5926 + ... + 6034.

It is an arithmetic number, because the mean of its divisors is an integer number (32340).

2⁶⁵¹⁸²⁰ 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 651820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (776160).

651820 is an abundant number, since it is smaller than the sum of its proper divisors (900500).

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

651820 is a wasteful number, since it uses less digits than its factorization.

651820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154 (or 152 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 651820 is about 807.3537019176. The cubic root of 651820 is about 86.7046841754.

Adding to 651820 its reverse (28156), we get a palindrome (679976).

The spelling of 651820 in words is "six hundred fifty-one thousand, eight hundred twenty".