845406640 has 80 divisors (see below), whose sum is σ = 2125676448. Its totient is φ = 310837248.

The previous prime is 845406631. The next prime is 845406643. The reversal of 845406640 is 46604548.

845406640 is a nontrivial binomial coefficient, being equal to C(41120, 2).

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

It is a self number, because there is not a number n which added to its sum of digits gives 845406640.

It is not an unprimeable number, because it can be changed into a prime (845406643) 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, 265699 + ... + 268861.

Almost surely, 2^845406640 is an apocalyptic number.

845406640 is a gapful number since it is divisible by the number (80) formed by its first and last digit.

845406640 is the 41119-th triangular number and also the 20560-th hexagonal number.

845406640 is the 13707-th centered nonagonal number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 845406640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1062838224).

845406640 is an abundant number, since it is smaller than the sum of its proper divisors (1280269808).

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

845406640 is a wasteful number, since it uses less digits than its factorization.

845406640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3446 (or 3440 counting only the distinct ones).

The product of its (nonzero) digits is 92160, while the sum is 37.

The square root of 845406640 is about 29075.8772868507. The cubic root of 845406640 is about 945.5588232886.

The spelling of 845406640 in words is "eight hundred forty-five million, four hundred six thousand, six hundred forty".