691320 has 64 divisors (see below), whose sum is σ = 2373120. Its totient is φ = 157824.

The previous prime is 691309. The next prime is 691333. The reversal of 691320 is 23196.

691320 = T₁₈₁ + T₁₈₂ + ... + T₂₁₅.

It is a Harshad number since it is a multiple of its sum of digits (21).

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 429 + ... + 1251.

It is an arithmetic number, because the mean of its divisors is an integer number (37080).

2⁶⁹¹³²⁰ is an apocalyptic number.

691320 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 691320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1186560).

691320 is an abundant number, since it is smaller than the sum of its proper divisors (1681800).

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

691320 is a wasteful number, since it uses less digits than its factorization.

691320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 844 (or 840 counting only the distinct ones).

The product of its (nonzero) digits is 324, while the sum is 21.

The square root of 691320 is about 831.4565532847. The cubic root of 691320 is about 88.4218723817.

The spelling of 691320 in words is "six hundred ninety-one thousand, three hundred twenty".