688961 has 16 divisors (see below), whose sum is σ = 868224. Its totient is φ = 532224.

The previous prime is 688957. The next prime is 688969. The reversal of 688961 is 169886.

688961 = T₄₉ + T₅₀ + ... + T₁₆₁.

It is not a de Polignac number, because 688961 - 2² = 688957 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (688969) 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 15 ways as a sum of consecutive naturals, for example, 6041 + ... + 6153.

It is an arithmetic number, because the mean of its divisors is an integer number (54264).

2⁶⁸⁸⁹⁶¹ is an apocalyptic number.

It is an amenable number.

688961 is a deficient number, since it is larger than the sum of its proper divisors (179263).

688961 is a wasteful number, since it uses less digits than its factorization.

688961 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 200.

The product of its digits is 20736, while the sum is 38.

The square root of 688961 is about 830.0367461745. The cubic root of 688961 is about 88.3211834086.

The spelling of 688961 in words is "six hundred eighty-eight thousand, nine hundred sixty-one".