646786140 has 384 divisors, whose sum is σ = 2479196160. Its totient is φ = 122664960.

The previous prime is 646786109. The next prime is 646786141. The reversal of 646786140 is 41687646.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a junction number, because it is equal to n+sod(n) for n = 646786092 and 646786101.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646786141) by changing a digit.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 7267216 + ... + 7267304.

It is an arithmetic number, because the mean of its divisors is an integer number (6456240).

Almost surely, 2^646786140 is an apocalyptic number.

646786140 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 646786140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1239598080).

646786140 is an abundant number, since it is smaller than the sum of its proper divisors (1832410020).

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

646786140 is a wasteful number, since it uses less digits than its factorization.

646786140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 154 (or 130 counting only the distinct ones).

The product of its (nonzero) digits is 193536, while the sum is 42.

The square root of 646786140 is about 25431.9904844273. The cubic root of 646786140 is about 864.8090683090.

The spelling of 646786140 in words is "six hundred forty-six million, seven hundred eighty-six thousand, one hundred forty".