681961408 has 42 divisors (see below), whose sum is σ = 1414733264. Its totient is φ = 326139264.

The previous prime is 681961391. The next prime is 681961513. The reversal of 681961408 is 804169186.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 23785 + ... + 43927.

Almost surely, 2^681961408 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 681961408, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (707366632).

681961408 is an abundant number, since it is smaller than the sum of its proper divisors (732771856).

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

681961408 is a wasteful number, since it uses less digits than its factorization.

681961408 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 20201 (or 20168 counting only the distinct ones).

The product of its (nonzero) digits is 82944, while the sum is 43.

The square root of 681961408 is about 26114.3908219204. The cubic root of 681961408 is about 880.2106107475.

The spelling of 681961408 in words is "six hundred eighty-one million, nine hundred sixty-one thousand, four hundred eight".