691072 has 16 divisors (see below), whose sum is σ = 1377000. Its totient is φ = 345472.

The previous prime is 691063. The next prime is 691079. The reversal of 691072 is 270196.

It is a tau number, because it is divible by the number of its divisors (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691079) by changing a digit.

691072 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 as a sum of consecutive naturals, namely, 2572 + ... + 2827.

2⁶⁹¹⁰⁷² is an apocalyptic number.

It is an amenable number.

691072 is a deficient number, since it is larger than the sum of its proper divisors (685928).

691072 is an equidigital number, since it uses as much as digits as its factorization.

691072 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5413 (or 5401 counting only the distinct ones).

The product of its (nonzero) digits is 756, while the sum is 25.

The square root of 691072 is about 831.3074040329. The cubic root of 691072 is about 88.4112978060.

The spelling of 691072 in words is "six hundred ninety-one thousand, seventy-two".