681649868 has 12 divisors (see below), whose sum is σ = 1212443232. Its totient is φ = 335237520.

The previous prime is 681649861. The next prime is 681649879. The reversal of 681649868 is 868946186.

It is a super-4 number, since 4×681649868⁴ (a number of 36 digits) contains 4444 as substring.

It is not an unprimeable number, because it can be changed into a prime (681649861) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1396580 + ... + 1397067.

It is an arithmetic number, because the mean of its divisors is an integer number (101036936).

Almost surely, 2^681649868 is an apocalyptic number.

It is an amenable number.

681649868 is a deficient number, since it is larger than the sum of its proper divisors (530793364).

681649868 is a wasteful number, since it uses less digits than its factorization.

681649868 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2793712 (or 2793710 counting only the distinct ones).

The product of its digits is 3981312, while the sum is 56.

The square root of 681649868 is about 26108.4252301819. The cubic root of 681649868 is about 880.0765549791.

The spelling of 681649868 in words is "six hundred eighty-one million, six hundred forty-nine thousand, eight hundred sixty-eight".