787681 has 6 divisors (see below), whose sum is σ = 823970. Its totient is φ = 752928.

The previous prime is 787667. The next prime is 787697. The reversal of 787681 is 186787.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 576081 + 211600 = 759^2 + 460^2 .

It is not a de Polignac number, because 787681 - 2⁵ = 787649 is a prime.

It is a super-2 number, since 2×787681² = 1240882715522, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 787681.

It is not an unprimeable number, because it can be changed into a prime (787601) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 216 + ... + 1273.

2⁷⁸⁷⁶⁸¹ is an apocalyptic number.

It is an amenable number.

787681 is a deficient number, since it is larger than the sum of its proper divisors (36289).

787681 is a wasteful number, since it uses less digits than its factorization.

787681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1535 (or 1512 counting only the distinct ones).

The product of its digits is 18816, while the sum is 37.

The square root of 787681 is about 887.5139435524. The cubic root of 787681 is about 92.3528119343.

The spelling of 787681 in words is "seven hundred eighty-seven thousand, six hundred eighty-one".