1643040240 has 80 divisors (see below), whose sum is σ = 5269082400. Its totient is φ = 423033856.

The previous prime is 1643040221. The next prime is 1643040247. The reversal of 1643040240 is 420403461.

It is a tau number, because it is divible by the number of its divisors (80).

It is a Harshad number since it is a multiple of its sum of digits (24).

It is a self number, because there is not a number n which added to its sum of digits gives 1643040240.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1643040247) 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, 111075 + ... + 124994.

It is an arithmetic number, because the mean of its divisors is an integer number (65863530).

Almost surely, 2^1643040240 is an apocalyptic number.

1643040240 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

1643040240 is an abundant number, since it is smaller than the sum of its proper divisors (3626042160).

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

1643040240 is a wasteful number, since it uses less digits than its factorization.

1643040240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 236114 (or 236108 counting only the distinct ones).

The product of its (nonzero) digits is 2304, while the sum is 24.

The square root of 1643040240 is about 40534.4327701770. The cubic root of 1643040240 is about 1180.0019726099.

The spelling of 1643040240 in words is "one billion, six hundred forty-three million, forty thousand, two hundred forty".