691421 has 4 divisors (see below), whose sum is σ = 703200. Its totient is φ = 679644.

The previous prime is 691409. The next prime is 691433. The reversal of 691421 is 124196.

It is a happy number.

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 an interprime number because it is at equal distance from previous prime (691409) and next prime (691433).

It is a cyclic number.

It is not a de Polignac number, because 691421 - 2¹⁰ = 690397 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5801 + ... + 5918.

It is an arithmetic number, because the mean of its divisors is an integer number (175800).

2⁶⁹¹⁴²¹ is an apocalyptic number.

It is an amenable number.

691421 is a deficient number, since it is larger than the sum of its proper divisors (11779).

691421 is a wasteful number, since it uses less digits than its factorization.

691421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11778.

The product of its digits is 432, while the sum is 23.

The square root of 691421 is about 831.5172878540. The cubic root of 691421 is about 88.4261782382.

The spelling of 691421 in words is "six hundred ninety-one thousand, four hundred twenty-one".