698640 has 80 divisors (see below), whose sum is σ = 2249856. Its totient is φ = 179200.

The previous prime is 698591. The next prime is 698641. The reversal of 698640 is 46896.

698640 = 110² + 111² + ... + 150².

It is a tau number, because it is divible by the number of its divisors (80).

It is an Ulam number.

It is a nialpdrome in base 16.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 698640.

It is not an unprimeable number, because it can be changed into a prime (698641) 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, 9805 + ... + 9875.

2⁶⁹⁸⁶⁴⁰ is an apocalyptic number.

698640 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 698640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1124928).

698640 is an abundant number, since it is smaller than the sum of its proper divisors (1551216).

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

698640 is a wasteful number, since it uses less digits than its factorization.

698640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 128 (or 122 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 33.

The square root of 698640 is about 835.8468759288. The cubic root of 698640 is about 88.7328605400.

The spelling of 698640 in words is "six hundred ninety-eight thousand, six hundred forty".