691887 has 16 divisors (see below), whose sum is σ = 1078272. Its totient is φ = 386400.

The previous prime is 691877. The next prime is 691891. The reversal of 691887 is 788196.

It is not a de Polignac number, because 691887 - 2⁴ = 691871 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691837) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 637 + ... + 1337.

It is an arithmetic number, because the mean of its divisors is an integer number (67392).

2⁶⁹¹⁸⁸⁷ is an apocalyptic number.

691887 is a deficient number, since it is larger than the sum of its proper divisors (386385).

691887 is a wasteful number, since it uses less digits than its factorization.

691887 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 758.

The product of its digits is 24192, while the sum is 39.

The square root of 691887 is about 831.7974513065. The cubic root of 691887 is about 88.4460394348.

The spelling of 691887 in words is "six hundred ninety-one thousand, eight hundred eighty-seven".