685193781 has 16 divisors (see below), whose sum is σ = 930325760. Its totient is φ = 448493760.

The previous prime is 685193749. The next prime is 685193869. The reversal of 685193781 is 187391586.

It is not a de Polignac number, because 685193781 - 2⁵ = 685193749 is a prime.

It is a super-2 number, since 2×685193781² = 938981035042151922, which contains 22 as substring.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 685193781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (685193081) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 34911 + ... + 50883.

It is an arithmetic number, because the mean of its divisors is an integer number (58145360).

Almost surely, 2^685193781 is an apocalyptic number.

It is an amenable number.

685193781 is a deficient number, since it is larger than the sum of its proper divisors (245131979).

685193781 is a wasteful number, since it uses less digits than its factorization.

685193781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16236.

The product of its digits is 362880, while the sum is 48.

The square root of 685193781 is about 26176.2063905372. The cubic root of 685193781 is about 881.5990987099.

The spelling of 685193781 in words is "six hundred eighty-five million, one hundred ninety-three thousand, seven hundred eighty-one".