691931646 has 120 divisors (see below), whose sum is σ = 1831898376. Its totient is φ = 194594400.

The previous prime is 691931633. The next prime is 691931663. The reversal of 691931646 is 646139196.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 59 ways as a sum of consecutive naturals, for example, 531196 + ... + 532496.

Almost surely, 2^691931646 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 691931646, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (915949188).

691931646 is an abundant number, since it is smaller than the sum of its proper divisors (1139966730).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

691931646 is a wasteful number, since it uses less digits than its factorization.

691931646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1396 (or 1380 counting only the distinct ones).

The product of its digits is 209952, while the sum is 45.

The square root of 691931646 is about 26304.5936292504. The cubic root of 691931646 is about 884.4794180562.

The spelling of 691931646 in words is "six hundred ninety-one million, nine hundred thirty-one thousand, six hundred forty-six".