684518401 has 4 divisors (see below), whose sum is σ = 782306752. Its totient is φ = 586730052.

The previous prime is 684518381. The next prime is 684518423. The reversal of 684518401 is 104815486.

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, and also an emirpimes, since its reverse is a distinct semiprime: 104815486 = 2 ⋅52407743.

It is a cyclic number.

It is not a de Polignac number, because 684518401 - 2⁵ = 684518369 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (684518101) 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, 48894165 + ... + 48894178.

It is an arithmetic number, because the mean of its divisors is an integer number (195576688).

Almost surely, 2^684518401 is an apocalyptic number.

It is an amenable number.

684518401 is a deficient number, since it is larger than the sum of its proper divisors (97788351).

684518401 is an equidigital number, since it uses as much as digits as its factorization.

684518401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 97788350.

The product of its (nonzero) digits is 30720, while the sum is 37.

The square root of 684518401 is about 26163.3025629411. The cubic root of 684518401 is about 881.3093460629.

The spelling of 684518401 in words is "six hundred eighty-four million, five hundred eighteen thousand, four hundred one".