680043781 has 4 divisors (see below), whose sum is σ = 680740812. Its totient is φ = 679346752.

The previous prime is 680043713. The next prime is 680043821. The reversal of 680043781 is 187340086.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 392436100 + 287607681 = 19810^2 + 16959^2 .

It is a cyclic number.

It is not a de Polignac number, because 680043781 - 2⁷ = 680043653 is a prime.

It is a super-2 number, since 2×680043781² = 924919088153551922, 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 680043781.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (680043701) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 347050 + ... + 349003.

It is an arithmetic number, because the mean of its divisors is an integer number (170185203).

Almost surely, 2^680043781 is an apocalyptic number.

It is an amenable number.

680043781 is a deficient number, since it is larger than the sum of its proper divisors (697031).

680043781 is an equidigital number, since it uses as much as digits as its factorization.

680043781 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 697030.

The product of its (nonzero) digits is 32256, while the sum is 37.

The square root of 680043781 is about 26077.6490696535. The cubic root of 680043781 is about 879.3848063403.

The spelling of 680043781 in words is "six hundred eighty million, forty-three thousand, seven hundred eighty-one".