681397864 has 32 divisors (see below), whose sum is σ = 1462334400. Its totient is φ = 291588480.

The previous prime is 681397853. The next prime is 681397867. The reversal of 681397864 is 468793186.

It is a happy number.

It is a Smith number, since the sum of its digits (52) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (681397867) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 29892 + ... + 47500.

It is an arithmetic number, because the mean of its divisors is an integer number (45697950).

Almost surely, 2^681397864 is an apocalyptic number.

It is an amenable number.

681397864 is an abundant number, since it is smaller than the sum of its proper divisors (780936536).

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

681397864 is a wasteful number, since it uses less digits than its factorization.

681397864 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18313 (or 18309 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 52.

The square root of 681397864 is about 26103.5986791094. The cubic root of 681397864 is about 879.9680876857.

The spelling of 681397864 in words is "six hundred eighty-one million, three hundred ninety-seven thousand, eight hundred sixty-four".