820840824261 has 24 divisors (see below), whose sum is σ = 1226746143480. Its totient is φ = 528270132096.

The previous prime is 820840824253. The next prime is 820840824263. The reversal of 820840824261 is 162428048028.

It can be written as a sum of positive squares in 4 ways, for example, as 304296760161 + 516544064100 = 551631^2 + 718710^2 .

It is not a de Polignac number, because 820840824261 - 2³ = 820840824253 is a prime.

It is a super-2 number, since 2×820840824261² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (820840824263) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1344315 + ... + 1857111.

It is an arithmetic number, because the mean of its divisors is an integer number (51114422645).

Almost surely, 2^820840824261 is an apocalyptic number.

It is an amenable number.

820840824261 is a deficient number, since it is larger than the sum of its proper divisors (405905319219).

820840824261 is a wasteful number, since it uses less digits than its factorization.

820840824261 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 518965 (or 518962 counting only the distinct ones).

The product of its (nonzero) digits is 393216, while the sum is 45.

The spelling of 820840824261 in words is "eight hundred twenty billion, eight hundred forty million, eight hundred twenty-four thousand, two hundred sixty-one".