691401 has 4 divisors (see below), whose sum is σ = 921872. Its totient is φ = 460932.

The previous prime is 691399. The next prime is 691409. The reversal of 691401 is 104196.

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 691401 - 2¹ = 691399 is a prime.

It is a D-number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (691409) 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, 115231 + ... + 115236.

It is an arithmetic number, because the mean of its divisors is an integer number (230468).

2⁶⁹¹⁴⁰¹ is an apocalyptic number.

It is an amenable number.

691401 is a deficient number, since it is larger than the sum of its proper divisors (230471).

691401 is a wasteful number, since it uses less digits than its factorization.

691401 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 230470.

The product of its (nonzero) digits is 216, while the sum is 21.

The square root of 691401 is about 831.5052615588. The cubic root of 691401 is about 88.4253256267.

Adding to 691401 its reverse (104196), we get a palindrome (795597).

It can be divided in two parts, 69 and 1401, that multiplied together give a palindrome (96669).

The spelling of 691401 in words is "six hundred ninety-one thousand, four hundred one".