651816 has 48 divisors (see below), whose sum is σ = 1928160. Its totient is φ = 197280.

The previous prime is 651811. The next prime is 651821. The reversal of 651816 is 618156.

651816 is a `hidden beast` number, since 651 + 8 + 1 + 6 = 666.

It is an interprime number because it is at equal distance from previous prime (651811) and next prime (651821).

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 651816.

It is not an unprimeable number, because it can be changed into a prime (651811) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 381 + ... + 1203.

It is an arithmetic number, because the mean of its divisors is an integer number (40170).

2⁶⁵¹⁸¹⁶ is an apocalyptic number.

651816 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 651816, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (964080).

651816 is an abundant number, since it is smaller than the sum of its proper divisors (1276344).

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

651816 is a wasteful number, since it uses less digits than its factorization.

651816 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 846 (or 839 counting only the distinct ones).

The product of its digits is 1440, while the sum is 27.

The square root of 651816 is about 807.3512246848. The cubic root of 651816 is about 86.7045068158.

It can be divided in two parts, 65 and 1816, that added together give a palindrome (1881).

The spelling of 651816 in words is "six hundred fifty-one thousand, eight hundred sixteen".