681691920 has 360 divisors, whose sum is σ = 2669668416. Its totient is φ = 143829504.

The previous prime is 681691909. The next prime is 681691939. The reversal of 681691920 is 29196186.

It is a Harshad number since it is a multiple of its sum of digits (42).

It is a zygodrome in base 14.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 71 ways as a sum of consecutive naturals, for example, 52437834 + ... + 52437846.

Almost surely, 2^681691920 is an apocalyptic number.

681691920 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 681691920, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1334834208).

681691920 is an abundant number, since it is smaller than the sum of its proper divisors (1987976496).

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

681691920 is an equidigital number, since it uses as much as digits as its factorization.

681691920 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 77 (or 30 counting only the distinct ones).

The product of its (nonzero) digits is 46656, while the sum is 42.

The square root of 681691920 is about 26109.2305516651. The cubic root of 681691920 is about 880.0946523533.

The spelling of 681691920 in words is "six hundred eighty-one million, six hundred ninety-one thousand, nine hundred twenty".