844521640 has 16 divisors (see below), whose sum is σ = 1900173780. Its totient is φ = 337808640.

The previous prime is 844521611. The next prime is 844521647. The reversal of 844521640 is 46125448.

It can be written as a sum of positive squares in 2 ways, for example, as 832784164 + 11737476 = 28858^2 + 3426^2 .

It is a junction number, because it is equal to n+sod(n) for n = 844521596 and 844521605.

It is not an unprimeable number, because it can be changed into a prime (844521647) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 10556481 + ... + 10556560.

Almost surely, 2^844521640 is an apocalyptic number.

It is an amenable number.

844521640 is an abundant number, since it is smaller than the sum of its proper divisors (1055652140).

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

844521640 is a wasteful number, since it uses less digits than its factorization.

844521640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21113052 (or 21113048 counting only the distinct ones).

The product of its (nonzero) digits is 30720, while the sum is 34.

The square root of 844521640 is about 29060.6545005442. The cubic root of 844521640 is about 945.2287605343.

The spelling of 844521640 in words is "eight hundred forty-four million, five hundred twenty-one thousand, six hundred forty".