685199906 has 4 divisors (see below), whose sum is σ = 1027799862. Its totient is φ = 342599952.

The previous prime is 685199903. The next prime is 685199917. The reversal of 685199906 is 609991586.

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

It can be written as a sum of positive squares in only one way, i.e., 426794281 + 258405625 = 20659^2 + 16075^2 .

It is a super-2 number, since 2×685199906² = 938997822364817672, which contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (685199903) 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 as a sum of consecutive naturals, namely, 171299975 + ... + 171299978.

Almost surely, 2^685199906 is an apocalyptic number.

685199906 is a deficient number, since it is larger than the sum of its proper divisors (342599956).

685199906 is a wasteful number, since it uses less digits than its factorization.

685199906 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 342599955.

The product of its (nonzero) digits is 1049760, while the sum is 53.

The square root of 685199906 is about 26176.3233858386. The cubic root of 685199906 is about 881.6017255962.

The spelling of 685199906 in words is "six hundred eighty-five million, one hundred ninety-nine thousand, nine hundred six".