691903 has 2 divisors, whose sum is σ = 691904. Its totient is φ = 691902.

The previous prime is 691897. The next prime is 691907. The reversal of 691903 is 309196.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 691903 - 2⁵ = 691871 is a prime.

It is a super-2 number, since 2×691903² = 957459522818, which contains 22 as substring.

It is equal to p₅₅₉₄₅ and since 691903 and 55945 have the same sum of digits, it is a Honaker prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691907) 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 as a sum of consecutive naturals, namely, 345951 + 345952.

It is an arithmetic number, because the mean of its divisors is an integer number (345952).

2⁶⁹¹⁹⁰³ is an apocalyptic number.

691903 is a deficient number, since it is larger than the sum of its proper divisors (1).

691903 is an equidigital number, since it uses as much as digits as its factorization.

691903 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1458, while the sum is 28.

The square root of 691903 is about 831.8070689769. The cubic root of 691903 is about 88.4467212059.

The spelling of 691903 in words is "six hundred ninety-one thousand, nine hundred three".