646261240 has 64 divisors (see below), whose sum is σ = 1511667360. Its totient is φ = 248440320.

The previous prime is 646261237. The next prime is 646261249. The reversal of 646261240 is 42162646.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646261249) 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, 120210 + ... + 125470.

Almost surely, 2^646261240 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 646261240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (755833680).

646261240 is an abundant number, since it is smaller than the sum of its proper divisors (865406120).

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

646261240 is a wasteful number, since it uses less digits than its factorization.

646261240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5392 (or 5388 counting only the distinct ones).

The product of its (nonzero) digits is 13824, while the sum is 31.

The square root of 646261240 is about 25421.6687099805. The cubic root of 646261240 is about 864.5750594121.

The spelling of 646261240 in words is "six hundred forty-six million, two hundred sixty-one thousand, two hundred forty".