689918491 has 4 divisors (see below), whose sum is σ = 690320632. Its totient is φ = 689516352.

The previous prime is 689918461. The next prime is 689918501. The reversal of 689918491 is 194819986.

689918491 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 689918491 - 2⁵ = 689918459 is a prime.

It is a super-3 number, since 3×689918491³ (a number of 27 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (689918441) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 198486 + ... + 201931.

It is an arithmetic number, because the mean of its divisors is an integer number (172580158).

Almost surely, 2^689918491 is an apocalyptic number.

689918491 is a deficient number, since it is larger than the sum of its proper divisors (402141).

689918491 is a wasteful number, since it uses less digits than its factorization.

689918491 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 402140.

The product of its digits is 1119744, while the sum is 55.

The square root of 689918491 is about 26266.2995300061. The cubic root of 689918491 is about 883.6207957573.

The spelling of 689918491 in words is "six hundred eighty-nine million, nine hundred eighteen thousand, four hundred ninety-one".