681492987 has 16 divisors (see below), whose sum is σ = 1153850880. Its totient is φ = 389424456.

The previous prime is 681492971. The next prime is 681492989. The reversal of 681492987 is 789294186.

681492987 is a `hidden beast` number, since 68 + 1 + 492 + 98 + 7 = 666.

It is not a de Polignac number, because 681492987 - 2⁴ = 681492971 is a prime.

It is not an unprimeable number, because it can be changed into a prime (681492989) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1802703 + ... + 1803080.

It is an arithmetic number, because the mean of its divisors is an integer number (72115680).

Almost surely, 2^681492987 is an apocalyptic number.

681492987 is a deficient number, since it is larger than the sum of its proper divisors (472357893).

681492987 is a wasteful number, since it uses less digits than its factorization.

681492987 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3605799 (or 3605793 counting only the distinct ones).

The product of its digits is 1741824, while the sum is 54.

The square root of 681492987 is about 26105.4206439965. The cubic root of 681492987 is about 880.0090335677.

The spelling of 681492987 in words is "six hundred eighty-one million, four hundred ninety-two thousand, nine hundred eighty-seven".