685631958 has 64 divisors (see below), whose sum is σ = 1546739712. Its totient is φ = 200821280.

The previous prime is 685631957. The next prime is 685631983. The reversal of 685631958 is 859136586.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 685631958.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685631951) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 256135 + ... + 258797.

It is an arithmetic number, because the mean of its divisors is an integer number (24167808).

Almost surely, 2^685631958 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 685631958, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (773369856).

685631958 is an abundant number, since it is smaller than the sum of its proper divisors (861107754).

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

685631958 is a wasteful number, since it uses less digits than its factorization.

685631958 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2809.

The product of its digits is 1555200, while the sum is 51.

The square root of 685631958 is about 26184.5748103726. The cubic root of 685631958 is about 881.7869843094.

The spelling of 685631958 in words is "six hundred eighty-five million, six hundred thirty-one thousand, nine hundred fifty-eight".