686646629 has 4 divisors (see below), whose sum is σ = 705204684. Its totient is φ = 668088576.

The previous prime is 686646617. The next prime is 686646671. The reversal of 686646629 is 926646686.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 332077729 + 354568900 = 18223^2 + 18830^2 .

It is not a de Polignac number, because 686646629 - 2²⁴ = 669869413 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (686646929) 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, 9278972 + ... + 9279045.

It is an arithmetic number, because the mean of its divisors is an integer number (176301171).

Almost surely, 2^686646629 is an apocalyptic number.

It is an amenable number.

686646629 is a deficient number, since it is larger than the sum of its proper divisors (18558055).

686646629 is a wasteful number, since it uses less digits than its factorization.

686646629 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 18558054.

The product of its digits is 4478976, while the sum is 53.

The square root of 686646629 is about 26203.9430048228. The cubic root of 686646629 is about 882.2217572533.

The spelling of 686646629 in words is "six hundred eighty-six million, six hundred forty-six thousand, six hundred twenty-nine".