691455 has 16 divisors (see below), whose sum is σ = 1142784. Its totient is φ = 356640.

The previous prime is 691451. The next prime is 691463. The reversal of 691455 is 554196.

It is not a de Polignac number, because 691455 - 2² = 691451 is a prime.

It is a super-2 number, since 2×691455² = 956220034050, which contains 22 as substring.

691455 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691451) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 279 + ... + 1208.

It is an arithmetic number, because the mean of its divisors is an integer number (71424).

2⁶⁹¹⁴⁵⁵ is an apocalyptic number.

691455 is a deficient number, since it is larger than the sum of its proper divisors (451329).

691455 is a wasteful number, since it uses less digits than its factorization.

691455 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1526.

The product of its digits is 5400, while the sum is 30.

The square root of 691455 is about 831.5377321565. The cubic root of 691455 is about 88.4276276402.

The spelling of 691455 in words is "six hundred ninety-one thousand, four hundred fifty-five".