691240 has 32 divisors (see below), whose sum is σ = 1697760. Its totient is φ = 251200.

The previous prime is 691231. The next prime is 691241. The reversal of 691240 is 42196.

691240 = T₃₄₉ + T₃₅₀ + ... + T₃₅₉.

It is a Harshad number since it is a multiple of its sum of digits (22).

It is not an unprimeable number, because it can be changed into a prime (691241) by changing a digit.

691240 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 346 + ... + 1225.

It is an arithmetic number, because the mean of its divisors is an integer number (53055).

2⁶⁹¹²⁴⁰ is an apocalyptic number.

It is an amenable number.

691240 is an abundant number, since it is smaller than the sum of its proper divisors (1006520).

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

691240 is a wasteful number, since it uses less digits than its factorization.

691240 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1593 (or 1589 counting only the distinct ones).

The product of its (nonzero) digits is 432, while the sum is 22.

The square root of 691240 is about 831.4084435463. The cubic root of 691240 is about 88.4184615046.

The spelling of 691240 in words is "six hundred ninety-one thousand, two hundred forty".