691398 has 24 divisors (see below), whose sum is σ = 1521936. Its totient is φ = 226800.

The previous prime is 691381. The next prime is 691399. The reversal of 691398 is 893196.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691399) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 1008 + ... + 1548.

It is an arithmetic number, because the mean of its divisors is an integer number (63414).

2⁶⁹¹³⁹⁸ is an apocalyptic number.

691398 is an abundant number, since it is smaller than the sum of its proper divisors (830538).

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

691398 is a wasteful number, since it uses less digits than its factorization.

691398 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 620 (or 617 counting only the distinct ones).

The product of its digits is 11664, while the sum is 36.

The square root of 691398 is about 831.5034575995. The cubic root of 691398 is about 88.4251977335.

It can be divided in two parts, 691 and 398, that added together give a square (1089 = 33²).

The spelling of 691398 in words is "six hundred ninety-one thousand, three hundred ninety-eight".