686693890 has 8 divisors (see below), whose sum is σ = 1236049020. Its totient is φ = 274677552.

The previous prime is 686693873. The next prime is 686693899. The reversal of 686693890 is 98396686.

It can be written as a sum of positive squares in 2 ways, for example, as 674492841 + 12201049 = 25971^2 + 3493^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a super-3 number, since 3×686693890³ (a number of 27 digits) contains 333 as substring.

It is not an unprimeable number, because it can be changed into a prime (686693899) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34334685 + ... + 34334704.

Almost surely, 2^686693890 is an apocalyptic number.

686693890 is a deficient number, since it is larger than the sum of its proper divisors (549355130).

686693890 is a wasteful number, since it uses less digits than its factorization.

686693890 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68669396.

The product of its (nonzero) digits is 3359232, while the sum is 55.

The square root of 686693890 is about 26204.8447810705. The cubic root of 686693890 is about 882.2419975168.

The spelling of 686693890 in words is "six hundred eighty-six million, six hundred ninety-three thousand, eight hundred ninety".