686147781 has 16 divisors (see below), whose sum is σ = 1000327680. Its totient is φ = 414891120.

The previous prime is 686147773. The next prime is 686147789. The reversal of 686147781 is 187741686.

It is an interprime number because it is at equal distance from previous prime (686147773) and next prime (686147789).

It is not a de Polignac number, because 686147781 - 2³ = 686147773 is a prime.

It is a super-2 number, since 2×686147781² = 941597554742447922, which contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 686147781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686147789) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 9195 + ... + 38168.

It is an arithmetic number, because the mean of its divisors is an integer number (62520480).

Almost surely, 2^686147781 is an apocalyptic number.

It is an amenable number.

686147781 is a deficient number, since it is larger than the sum of its proper divisors (314179899).

686147781 is a wasteful number, since it uses less digits than its factorization.

686147781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 47816.

The product of its digits is 451584, while the sum is 48.

The square root of 686147781 is about 26194.4227078972. The cubic root of 686147781 is about 882.0080611251.

The spelling of 686147781 in words is "six hundred eighty-six million, one hundred forty-seven thousand, seven hundred eighty-one".