691734321 has 6 divisors (see below), whose sum is σ = 999171810. Its totient is φ = 461156208.

The previous prime is 691734319. The next prime is 691734343. The reversal of 691734321 is 123437196.

It can be written as a sum of positive squares in only one way, i.e., 659924721 + 31809600 = 25689^2 + 5640^2 .

It is not a de Polignac number, because 691734321 - 2¹ = 691734319 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (691734221) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 38429676 + ... + 38429693.

It is an arithmetic number, because the mean of its divisors is an integer number (166528635).

Almost surely, 2^691734321 is an apocalyptic number.

It is an amenable number.

691734321 is a deficient number, since it is larger than the sum of its proper divisors (307437489).

691734321 is a wasteful number, since it uses less digits than its factorization.

691734321 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76859375 (or 76859372 counting only the distinct ones).

The product of its digits is 27216, while the sum is 36.

The square root of 691734321 is about 26300.8425910654. The cubic root of 691734321 is about 884.3953314775.

The spelling of 691734321 in words is "six hundred ninety-one million, seven hundred thirty-four thousand, three hundred twenty-one".