688720542 has 32 divisors (see below), whose sum is σ = 1413345024. Its totient is φ = 223608000.

The previous prime is 688720481. The next prime is 688720633. The reversal of 688720542 is 245027886.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 688720494 and 688720503.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 176917 + ... + 180767.

It is an arithmetic number, because the mean of its divisors is an integer number (44167032).

Almost surely, 2^688720542 is an apocalyptic number.

688720542 is an abundant number, since it is smaller than the sum of its proper divisors (724624482).

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

688720542 is a wasteful number, since it uses less digits than its factorization.

688720542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4624.

The product of its (nonzero) digits is 215040, while the sum is 42.

The square root of 688720542 is about 26243.4857059804. The cubic root of 688720542 is about 883.1090706188.

The spelling of 688720542 in words is "six hundred eighty-eight million, seven hundred twenty thousand, five hundred forty-two".