691734389 has 2 divisors, whose sum is σ = 691734390. Its totient is φ = 691734388.

The previous prime is 691734377. The next prime is 691734409. The reversal of 691734389 is 983437196.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 684711889 + 7022500 = 26167^2 + 2650^2 .

It is a cyclic number.

It is not a de Polignac number, because 691734389 - 2¹⁶ = 691668853 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (691734319) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 345867194 + 345867195.

It is an arithmetic number, because the mean of its divisors is an integer number (345867195).

Almost surely, 2^691734389 is an apocalyptic number.

It is an amenable number.

691734389 is a deficient number, since it is larger than the sum of its proper divisors (1).

691734389 is an equidigital number, since it uses as much as digits as its factorization.

691734389 is an evil number, because the sum of its binary digits is even.

The product of its digits is 979776, while the sum is 50.

The square root of 691734389 is about 26300.8438837996. The cubic root of 691734389 is about 884.3953604572.

The spelling of 691734389 in words is "six hundred ninety-one million, seven hundred thirty-four thousand, three hundred eighty-nine".