688681137 has 4 divisors (see below), whose sum is σ = 918241520. Its totient is φ = 459120756.

The previous prime is 688681121. The next prime is 688681159. The reversal of 688681137 is 731186886.

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 not a de Polignac number, because 688681137 - 2⁴ = 688681121 is a prime.

It is a super-2 number, since 2×688681137² = 948563416919225538, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (688681117) 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, 114780187 + ... + 114780192.

It is an arithmetic number, because the mean of its divisors is an integer number (229560380).

Almost surely, 2^688681137 is an apocalyptic number.

It is an amenable number.

688681137 is a deficient number, since it is larger than the sum of its proper divisors (229560383).

688681137 is a wasteful number, since it uses less digits than its factorization.

688681137 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 229560382.

The product of its digits is 387072, while the sum is 48.

The square root of 688681137 is about 26242.7349375022. The cubic root of 688681137 is about 883.0922279981.

The spelling of 688681137 in words is "six hundred eighty-eight million, six hundred eighty-one thousand, one hundred thirty-seven".