685721078881 has 8 divisors (see below), whose sum is σ = 729253021280. Its totient is φ = 642933272448.

The previous prime is 685721078879. The next prime is 685721078891. The reversal of 685721078881 is 188870127586.

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

It is a cyclic number.

It is not a de Polignac number, because 685721078881 - 2¹ = 685721078879 is a prime.

It is a super-2 number, since 2×685721078881² (a number of 24 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (685721078891) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 186032091 + ... + 186035776.

It is an arithmetic number, because the mean of its divisors is an integer number (91156627660).

Almost surely, 2^685721078881 is an apocalyptic number.

It is an amenable number.

685721078881 is a deficient number, since it is larger than the sum of its proper divisors (43531942399).

685721078881 is a wasteful number, since it uses less digits than its factorization.

685721078881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 372067983.

The product of its (nonzero) digits is 12042240, while the sum is 61.

The spelling of 685721078881 in words is "six hundred eighty-five billion, seven hundred twenty-one million, seventy-eight thousand, eight hundred eighty-one".