687394531 has 4 divisors (see below), whose sum is σ = 687462552. Its totient is φ = 687326512.

The previous prime is 687394501. The next prime is 687394549. The reversal of 687394531 is 135493786.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 687394531 - 2¹⁹ = 686870243 is a prime.

It is a super-2 number, since 2×687394531² = 945022482497419922, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (687394501) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 15490 + ... + 40183.

It is an arithmetic number, because the mean of its divisors is an integer number (171865638).

Almost surely, 2^687394531 is an apocalyptic number.

687394531 is a deficient number, since it is larger than the sum of its proper divisors (68021).

687394531 is a wasteful number, since it uses less digits than its factorization.

687394531 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 68020.

The product of its digits is 544320, while the sum is 46.

The square root of 687394531 is about 26218.2099121965. The cubic root of 687394531 is about 882.5419491224.

The spelling of 687394531 in words is "six hundred eighty-seven million, three hundred ninety-four thousand, five hundred thirty-one".