681782871420 has 768 divisors, whose sum is σ = 2568609792000. Its totient is φ = 146779776000.

The previous prime is 681782871383. The next prime is 681782871457. The reversal of 681782871420 is 24178287186.

681782871420 is a `hidden beast` number, since 6 + 81 + 78 + 2 + 8 + 71 + 420 = 666.

It is an interprime number because it is at equal distance from previous prime (681782871383) and next prime (681782871457).

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 255 ways as a sum of consecutive naturals, for example, 2716266295 + ... + 2716266545.

It is an arithmetic number, because the mean of its divisors is an integer number (3344544000).

Almost surely, 2^681782871420 is an apocalyptic number.

681782871420 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 681782871420, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1284304896000).

681782871420 is an abundant number, since it is smaller than the sum of its proper divisors (1886826920580).

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

681782871420 is a wasteful number, since it uses less digits than its factorization.

681782871420 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 655 (or 647 counting only the distinct ones).

The product of its (nonzero) digits is 2408448, while the sum is 54.

The spelling of 681782871420 in words is "six hundred eighty-one billion, seven hundred eighty-two million, eight hundred seventy-one thousand, four hundred twenty".