688126121 has 4 divisors (see below), whose sum is σ = 718044672. Its totient is φ = 658207572.

The previous prime is 688126091. The next prime is 688126129. The reversal of 688126121 is 121621886.

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 not a de Polignac number, because 688126121 - 2⁶ = 688126057 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (688126129) 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, 14959241 + ... + 14959286.

It is an arithmetic number, because the mean of its divisors is an integer number (179511168).

Almost surely, 2^688126121 is an apocalyptic number.

It is an amenable number.

688126121 is a deficient number, since it is larger than the sum of its proper divisors (29918551).

688126121 is a wasteful number, since it uses less digits than its factorization.

688126121 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29918550.

The product of its digits is 9216, while the sum is 35.

The square root of 688126121 is about 26232.1581460619. The cubic root of 688126121 is about 882.8549328669.

The spelling of 688126121 in words is "six hundred eighty-eight million, one hundred twenty-six thousand, one hundred twenty-one".