691400 has 24 divisors (see below), whose sum is σ = 1607970. Its totient is φ = 276480.

The previous prime is 691399. The next prime is 691409. The reversal of 691400 is 4196.

It can be written as a sum of positive squares in 3 ways, for example, as 289444 + 401956 = 538^2 + 634^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is a congruent 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 5 ways as a sum of consecutive naturals, for example, 1529 + ... + 1928.

2⁶⁹¹⁴⁰⁰ is an apocalyptic number.

It is an amenable number.

691400 is an abundant number, since it is smaller than the sum of its proper divisors (916570).

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

691400 is a wasteful number, since it uses less digits than its factorization.

691400 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3473 (or 3464 counting only the distinct ones).

The product of its (nonzero) digits is 216, while the sum is 20.

The square root of 691400 is about 831.5046602395. The cubic root of 691400 is about 88.4252829957.

Adding to 691400 its reverse (4196), we get a palindrome (695596).

The spelling of 691400 in words is "six hundred ninety-one thousand, four hundred".