681339987 has 12 divisors (see below), whose sum is σ = 989259544. Its totient is φ = 451872000.

The previous prime is 681339983. The next prime is 681340001. The reversal of 681339987 is 789933186.

It is not a de Polignac number, because 681339987 - 2² = 681339983 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (681339983) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 194389 + ... + 197862.

Almost surely, 2^681339987 is an apocalyptic number.

681339987 is a deficient number, since it is larger than the sum of its proper divisors (307919557).

681339987 is a wasteful number, since it uses less digits than its factorization.

681339987 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 392450 (or 392447 counting only the distinct ones).

The product of its digits is 1959552, while the sum is 54.

The square root of 681339987 is about 26102.4900536328. The cubic root of 681339987 is about 879.9431725528.

The spelling of 681339987 in words is "six hundred eighty-one million, three hundred thirty-nine thousand, nine hundred eighty-seven".