684566401 has 4 divisors (see below), whose sum is σ = 685927872. Its totient is φ = 683204932.

The previous prime is 684566383. The next prime is 684566429. The reversal of 684566401 is 104665486.

It is a happy number.

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-684566401 is a prime.

It is a Smith number, since the sum of its digits (40) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (684566471) 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, 679981 + ... + 680986.

It is an arithmetic number, because the mean of its divisors is an integer number (171481968).

Almost surely, 2^684566401 is an apocalyptic number.

It is an amenable number.

684566401 is a deficient number, since it is larger than the sum of its proper divisors (1361471).

684566401 is a wasteful number, since it uses less digits than its factorization.

684566401 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1361470.

The product of its (nonzero) digits is 138240, while the sum is 40.

The square root of 684566401 is about 26164.2198622470. The cubic root of 684566401 is about 881.3299453922.

The spelling of 684566401 in words is "six hundred eighty-four million, five hundred sixty-six thousand, four hundred one".