781285820 has 24 divisors (see below), whose sum is σ = 1875086304. Its totient is φ = 267869376.

The previous prime is 781285807. The next prime is 781285823. The reversal of 781285820 is 28582187.

It is a super-2 number, since 2×781285820² = 1220815065066144800, which contains 22 as substring.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (781285823) 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 7 ways as a sum of consecutive naturals, for example, 2790167 + ... + 2790446.

It is an arithmetic number, because the mean of its divisors is an integer number (78128596).

Almost surely, 2^781285820 is an apocalyptic number.

781285820 is a gapful number since it is divisible by the number (70) formed by its first and last digit.

It is an amenable number.

781285820 is an abundant number, since it is smaller than the sum of its proper divisors (1093800484).

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

781285820 is a wasteful number, since it uses less digits than its factorization.

781285820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5580629 (or 5580627 counting only the distinct ones).

The product of its (nonzero) digits is 71680, while the sum is 41.

The square root of 781285820 is about 27951.4904790424. The cubic root of 781285820 is about 921.0219503925.

The spelling of 781285820 in words is "seven hundred eighty-one million, two hundred eighty-five thousand, eight hundred twenty".