783540821 has 24 divisors (see below), whose sum is σ = 948112920. Its totient is φ = 644861952.

The previous prime is 783540811. The next prime is 783540847. The reversal of 783540821 is 128045387.

It can be written as a sum of positive squares in 4 ways, for example, as 96314596 + 687226225 = 9814^2 + 26215^2 .

It is not a de Polignac number, because 783540821 - 2¹⁴ = 783524437 is a prime.

It is a super-2 number, since 2×783540821² = 1227872436346708082, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (783540811) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 272825 + ... + 275681.

It is an arithmetic number, because the mean of its divisors is an integer number (39504705).

Almost surely, 2^783540821 is an apocalyptic number.

It is an amenable number.

783540821 is a deficient number, since it is larger than the sum of its proper divisors (164572099).

783540821 is a wasteful number, since it uses less digits than its factorization.

783540821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3093 (or 3086 counting only the distinct ones).

The product of its (nonzero) digits is 53760, while the sum is 38.

The square root of 783540821 is about 27991.7991740438. The cubic root of 783540821 is about 921.9072049284.

The spelling of 783540821 in words is "seven hundred eighty-three million, five hundred forty thousand, eight hundred twenty-one".