646920 has 64 divisors (see below), whose sum is σ = 2160000. Its totient is φ = 172224.

The previous prime is 646913. The next prime is 646927. The reversal of 646920 is 29646.

646920 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is an interprime number because it is at equal distance from previous prime (646913) and next prime (646927).

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nialpdrome in base 15.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 646920.

It is not an unprimeable number, because it can be changed into a prime (646927) by changing a digit.

646920 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 15 ways as a sum of consecutive naturals, for example, 781 + ... + 1379.

It is an arithmetic number, because the mean of its divisors is an integer number (33750).

2⁶⁴⁶⁹²⁰ is an apocalyptic number.

646920 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 646920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1080000).

646920 is an abundant number, since it is smaller than the sum of its proper divisors (1513080).

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

646920 is a wasteful number, since it uses less digits than its factorization.

646920 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 619 (or 609 counting only the distinct ones).

The product of its (nonzero) digits is 2592, while the sum is 27.

The square root of 646920 is about 804.3133717650. The cubic root of 646920 is about 86.4868724997.

The spelling of 646920 in words is "six hundred forty-six thousand, nine hundred twenty".