646205040 has 240 divisors, whose sum is σ = 2424615648. Its totient is φ = 159003648.

The previous prime is 646205039. The next prime is 646205041. The reversal of 646205040 is 40502646.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (646205039) and next prime (646205041).

It is a tau number, because it is divible by the number of its divisors (240).

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

It is a junction number, because it is equal to n+sod(n) for n = 646204995 and 646205013.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646205041) by changing a digit.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 251442 + ... + 253998.

Almost surely, 2^646205040 is an apocalyptic number.

646205040 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 646205040, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1212307824).

646205040 is an abundant number, since it is smaller than the sum of its proper divisors (1778410608).

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

646205040 is a wasteful number, since it uses less digits than its factorization.

646205040 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2598 (or 2580 counting only the distinct ones).

The product of its (nonzero) digits is 5760, while the sum is 27.

The square root of 646205040 is about 25420.5633297140. The cubic root of 646205040 is about 864.5499970360.

Adding to 646205040 its reverse (40502646), we get a palindrome (686707686).

The spelling of 646205040 in words is "six hundred forty-six million, two hundred five thousand, forty".