651840 has 112 divisors (see below), whose sum is σ = 2389632. Its totient is φ = 147456.

The previous prime is 651839. The next prime is 651841. The reversal of 651840 is 48156.

651840 = T₆₄ + T₆₅ + ... + T₁₆₀.

It is an interprime number because it is at equal distance from previous prime (651839) and next prime (651841).

It is a tau number, because it is divible by the number of its divisors (112).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 651840.

It is not an unprimeable number, because it can be changed into a prime (651841) 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, 6672 + ... + 6768.

It is an arithmetic number, because the mean of its divisors is an integer number (21336).

2⁶⁵¹⁸⁴⁰ is an apocalyptic number.

651840 is a gapful number since it is divisible by the number (60) 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 651840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1194816).

651840 is an abundant number, since it is smaller than the sum of its proper divisors (1737792).

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

651840 is a wasteful number, since it uses less digits than its factorization.

651840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 124 (or 114 counting only the distinct ones).

The product of its (nonzero) digits is 960, while the sum is 24.

The square root of 651840 is about 807.3660879675. The cubic root of 651840 is about 86.7055709621.

Adding to 651840 its reverse (48156), we get a palindrome (699996).

The spelling of 651840 in words is "six hundred fifty-one thousand, eight hundred forty".