646355440 has 40 divisors (see below), whose sum is σ = 1504189440. Its totient is φ = 258299136.

The previous prime is 646355431. The next prime is 646355449. The reversal of 646355440 is 44553646.

It is an interprime number because it is at equal distance from previous prime (646355431) and next prime (646355449).

It is a tau number, because it is divible by the number of its divisors (40).

It is a self number, because there is not a number n which added to its sum of digits gives 646355440.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (646355449) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 99162 + ... + 105478.

It is an arithmetic number, because the mean of its divisors is an integer number (37604736).

Almost surely, 2^646355440 is an apocalyptic number.

It is an amenable number.

646355440 is an abundant number, since it is smaller than the sum of its proper divisors (857834000).

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

646355440 is a wasteful number, since it uses less digits than its factorization.

646355440 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7609 (or 7603 counting only the distinct ones).

The product of its (nonzero) digits is 172800, while the sum is 37.

The square root of 646355440 is about 25423.5213926002. The cubic root of 646355440 is about 864.6170646203.

The spelling of 646355440 in words is "six hundred forty-six million, three hundred fifty-five thousand, four hundred forty".