690491 has 2 divisors, whose sum is σ = 690492. Its totient is φ = 690490.

The previous prime is 690467. The next prime is 690493. The reversal of 690491 is 194096.

690491 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 690491 - 2⁶ = 690427 is a prime.

It is a Sophie Germain prime.

Together with 690493, it forms a pair of twin primes.

It is a Chen prime.

It is an Ulam number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 690491.

It is not a weakly prime, because it can be changed into another prime (690493) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345245 + 345246.

It is an arithmetic number, because the mean of its divisors is an integer number (345246).

2⁶⁹⁰⁴⁹¹ is an apocalyptic number.

690491 is a deficient number, since it is larger than the sum of its proper divisors (1).

690491 is an equidigital number, since it uses as much as digits as its factorization.

690491 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 1944, while the sum is 29.

The square root of 690491 is about 830.9578810024. The cubic root of 690491 is about 88.3865143942.

The spelling of 690491 in words is "six hundred ninety thousand, four hundred ninety-one".