686218406 has 4 divisors (see below), whose sum is σ = 1029327612. Its totient is φ = 343109202.

The previous prime is 686218399. The next prime is 686218433. The reversal of 686218406 is 604812686.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 171554600 + ... + 171554603.

It is an arithmetic number, because the mean of its divisors is an integer number (257331903).

Almost surely, 2^686218406 is an apocalyptic number.

686218406 is a deficient number, since it is larger than the sum of its proper divisors (343109206).

686218406 is a wasteful number, since it uses less digits than its factorization.

686218406 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 343109205.

The product of its (nonzero) digits is 110592, while the sum is 41.

The square root of 686218406 is about 26195.7707655263. The cubic root of 686218406 is about 882.0383217016.

The spelling of 686218406 in words is "six hundred eighty-six million, two hundred eighteen thousand, four hundred six".