684669881 has 4 divisors (see below), whose sum is σ = 782479872. Its totient is φ = 586859892.

The previous prime is 684669871. The next prime is 684669889. The reversal of 684669881 is 188966486.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-684669881 is a prime.

It is a super-2 number, since 2×684669881² = 937545691897108322, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (684669889) 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, 48904985 + ... + 48904998.

It is an arithmetic number, because the mean of its divisors is an integer number (195619968).

Almost surely, 2^684669881 is an apocalyptic number.

It is an amenable number.

684669881 is a deficient number, since it is larger than the sum of its proper divisors (97809991).

684669881 is an equidigital number, since it uses as much as digits as its factorization.

684669881 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97809990.

The product of its digits is 3981312, while the sum is 56.

The square root of 684669881 is about 26166.1972972765. The cubic root of 684669881 is about 881.3743508376.

The spelling of 684669881 in words is "six hundred eighty-four million, six hundred sixty-nine thousand, eight hundred eighty-one".