691145 has 32 divisors (see below), whose sum is σ = 1075200. Its totient is φ = 423360.

The previous prime is 691129. The next prime is 691147. The reversal of 691145 is 541196.

691145 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is not a de Polignac number, because 691145 - 2⁴ = 691129 is a prime.

It is a super-2 number, since 2×691145² = 955362822050, which contains 22 as substring.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (691147) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 22280 + ... + 22310.

It is an arithmetic number, because the mean of its divisors is an integer number (33600).

2⁶⁹¹¹⁴⁵ is an apocalyptic number.

691145 is a gapful number since it is divisible by the number (65) formed by its first and last digit.

It is an amenable number.

691145 is a deficient number, since it is larger than the sum of its proper divisors (384055).

691145 is a wasteful number, since it uses less digits than its factorization.

691145 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 70 (or 56 counting only the distinct ones).

The product of its digits is 1080, while the sum is 26.

The square root of 691145 is about 831.3513096159. The cubic root of 691145 is about 88.4144107462.

The spelling of 691145 in words is "six hundred ninety-one thousand, one hundred forty-five".