2820806781 has 16 divisors (see below), whose sum is σ = 4057322304. Its totient is φ = 1732909824.

The previous prime is 2820806767. The next prime is 2820806789. The reversal of 2820806781 is 1876080282.

It is not a de Polignac number, because 2820806781 - 2¹⁸ = 2820544637 is a prime.

It is a super-2 number, since 2×2820806781² = 15913901791471163922, which contains 22 as substring.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2820806789) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 38716 + ... + 84501.

It is an arithmetic number, because the mean of its divisors is an integer number (253582644).

Almost surely, 2^2820806781 is an apocalyptic number.

It is an amenable number.

2820806781 is a deficient number, since it is larger than the sum of its proper divisors (1236515523).

2820806781 is a wasteful number, since it uses less digits than its factorization.

2820806781 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 123820.

The product of its (nonzero) digits is 86016, while the sum is 42.

The square root of 2820806781 is about 53111.2679287550. The cubic root of 2820806781 is about 1412.9423627763.

The spelling of 2820806781 in words is "two billion, eight hundred twenty million, eight hundred six thousand, seven hundred eighty-one".