685636993024 has 45 divisors (see below), whose sum is σ = 1371444140577. Its totient is φ = 342765502464.

The previous prime is 685636993021. The next prime is 685636993031. The reversal of 685636993024 is 420399636586.

It is a happy number.

The square root of 685636993024 is 828032.

It is a perfect power (a square), and thus also a powerful number.

It can be written as a sum of positive squares in only one way, i.e., 35356033024 + 650280960000 = 188032^2 + 806400^2 .

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (685636993021) by changing a digit.

It is a polite number, since it can be written in 2 ways as a sum of consecutive naturals, for example, 105984862 + ... + 105991330.

Almost surely, 2^685636993024 is an apocalyptic number.

685636993024 is a gapful number since it is divisible by the number (64) formed by its first and last digit.

685636993024 is the 828032-nd square number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 685636993024

685636993024 is an abundant number, since it is smaller than the sum of its proper divisors (685807147553).

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

685636993024 is an frugal number, since it uses more digits than its factorization.

685636993024 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12966 (or 6471 counting only the distinct ones).

The product of its (nonzero) digits is 50388480, while the sum is 61.

The spelling of 685636993024 in words is "six hundred eighty-five billion, six hundred thirty-six million, nine hundred ninety-three thousand, twenty-four".