688428 has 36 divisors (see below), whose sum is σ = 1875328. Its totient is φ = 211680.

The previous prime is 688423. The next prime is 688433. The reversal of 688428 is 824886.

688428 = T₂₁₇ + T₂₁₈ + ... + T₂₄₂.

It is an interprime number because it is at equal distance from previous prime (688423) and next prime (688433).

It is a tau number, because it is divible by the number of its divisors (36).

It is a super-2 number, since 2×688428² = 947866222368, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 688392 and 688401.

It is not an unprimeable number, because it can be changed into a prime (688423) 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 11 ways as a sum of consecutive naturals, for example, 268 + ... + 1203.

2⁶⁸⁸⁴²⁸ is an apocalyptic number.

It is an amenable number.

688428 is an abundant number, since it is smaller than the sum of its proper divisors (1186900).

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

688428 is a wasteful number, since it uses less digits than its factorization.

688428 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1494 (or 1489 counting only the distinct ones).

The product of its digits is 24576, while the sum is 36.

The square root of 688428 is about 829.7156139305. The cubic root of 688428 is about 88.2984015987.

The spelling of 688428 in words is "six hundred eighty-eight thousand, four hundred twenty-eight".