685220090 has 8 divisors (see below), whose sum is σ = 1233396180. Its totient is φ = 274088032.

The previous prime is 685220087. The next prime is 685220111. The reversal of 685220090 is 90022586.

It can be written as a sum of positive squares in 2 ways, for example, as 637209049 + 48011041 = 25243^2 + 6929^2 .

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

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 34260995 + ... + 34261014.

Almost surely, 2^685220090 is an apocalyptic number.

685220090 is a deficient number, since it is larger than the sum of its proper divisors (548176090).

685220090 is a wasteful number, since it uses less digits than its factorization.

685220090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 68522016.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 685220090 is about 26176.7089222461. The cubic root of 685220090 is about 881.6103819870.

The spelling of 685220090 in words is "six hundred eighty-five million, two hundred twenty thousand, ninety".