685980090 has 160 divisors (see below), whose sum is σ = 2017281024. Its totient is φ = 166510080.

The previous prime is 685980067. The next prime is 685980101. The reversal of 685980090 is 90089586.

It is a Smith number, since the sum of its digits (45) coincides with the sum of the digits of its prime factors.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is a Curzon number.

It is an unprimeable number.

It is a polite number, since it can be written in 79 ways as a sum of consecutive naturals, for example, 426067 + ... + 427673.

Almost surely, 2^685980090 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 685980090, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1008640512).

685980090 is an abundant number, since it is smaller than the sum of its proper divisors (1331300934).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

685980090 is a wasteful number, since it uses less digits than its factorization.

685980090 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1674 (or 1665 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The square root of 685980090 is about 26191.2216209935. The cubic root of 685980090 is about 881.9362025214.

The spelling of 685980090 in words is "six hundred eighty-five million, nine hundred eighty thousand, ninety".