688001540 has 24 divisors (see below), whose sum is σ = 1454506200. Its totient is φ = 273352448.

The previous prime is 688001519. The next prime is 688001549. The reversal of 688001540 is 45100886.

It can be written as a sum of positive squares in 4 ways, for example, as 15429184 + 672572356 = 3928^2 + 25934^2 .

It is a super-2 number, since 2×688001540² = 946692238084743200, which contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 688001497 and 688001506.

It is not an unprimeable number, because it can be changed into a prime (688001549) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 112457 + ... + 118416.

It is an arithmetic number, because the mean of its divisors is an integer number (60604425).

Almost surely, 2^688001540 is an apocalyptic number.

It is an amenable number.

688001540 is an abundant number, since it is smaller than the sum of its proper divisors (766504660).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

688001540 is a wasteful number, since it uses less digits than its factorization.

688001540 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 231031 (or 231029 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 32.

The square root of 688001540 is about 26229.7834531664. The cubic root of 688001540 is about 882.8016511670.

The spelling of 688001540 in words is "six hundred eighty-eight million, one thousand, five hundred forty".