781828020 has 36 divisors (see below), whose sum is σ = 2371545540. Its totient is φ = 208487424.

The previous prime is 781828009. The next prime is 781828027. The reversal of 781828020 is 20828187.

It can be written as a sum of positive squares in 2 ways, for example, as 121749156 + 660078864 = 11034^2 + 25692^2 .

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-3 number, since 3×781828020³ (a number of 28 digits) contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (781828027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 2171565 + ... + 2171924.

It is an arithmetic number, because the mean of its divisors is an integer number (65876265).

Almost surely, 2^781828020 is an apocalyptic number.

It is an amenable number.

781828020 is an abundant number, since it is smaller than the sum of its proper divisors (1589717520).

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

781828020 is a wasteful number, since it uses less digits than its factorization.

781828020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4343504 (or 4343499 counting only the distinct ones).

The product of its (nonzero) digits is 14336, while the sum is 36.

The square root of 781828020 is about 27961.1877430126. The cubic root of 781828020 is about 921.2349593465.

The spelling of 781828020 in words is "seven hundred eighty-one million, eight hundred twenty-eight thousand, twenty".