691834421 has 2 divisors, whose sum is σ = 691834422. Its totient is φ = 691834420.

The previous prime is 691834379. The next prime is 691834427. The reversal of 691834421 is 124438196.

691834421 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 can be written as a sum of positive squares in only one way, i.e., 685654225 + 6180196 = 26185^2 + 2486^2 .

It is a cyclic number.

It is not a de Polignac number, because 691834421 - 2⁶ = 691834357 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691834427) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345917210 + 345917211.

It is an arithmetic number, because the mean of its divisors is an integer number (345917211).

Almost surely, 2^691834421 is an apocalyptic number.

It is an amenable number.

691834421 is a deficient number, since it is larger than the sum of its proper divisors (1).

691834421 is an equidigital number, since it uses as much as digits as its factorization.

691834421 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 41472, while the sum is 38.

The square root of 691834421 is about 26302.7455030839. The cubic root of 691834421 is about 884.4379893304.

The spelling of 691834421 in words is "six hundred ninety-one million, eight hundred thirty-four thousand, four hundred twenty-one".