684531 has 16 divisors (see below), whose sum is σ = 1029920. Its totient is φ = 454896.

The previous prime is 684527. The next prime is 684547. The reversal of 684531 is 135486.

It is not a de Polignac number, because 684531 - 2² = 684527 is a prime.

It is a super-2 number, since 2×684531² = 937165379922, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

684531 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 684495 and 684504.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 684531.

It is not an unprimeable number, because it can be changed into a prime (684581) 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, 2031 + ... + 2343.

It is an arithmetic number, because the mean of its divisors is an integer number (64370).

684531 is a Friedman number, since it can be written as (3^8*(5^4+1))/6, using all its digits and the basic arithmetic operations.

2⁶⁸⁴⁵³¹ is an apocalyptic number.

684531 is a deficient number, since it is larger than the sum of its proper divisors (345389).

684531 is an frugal number, since it uses more digits than its factorization.

684531 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 334 (or 316 counting only the distinct ones).

The product of its digits is 2880, while the sum is 27.

The square root of 684531 is about 827.3638860864. The cubic root of 684531 is about 88.1314753051.

The spelling of 684531 in words is "six hundred eighty-four thousand, five hundred thirty-one".