691966840 has 64 divisors (see below), whose sum is σ = 1602205920. Its totient is φ = 268960000.

The previous prime is 691966819. The next prime is 691966843. The reversal of 691966840 is 48669196.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691966843) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2756715 + ... + 2756965.

Almost surely, 2^691966840 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 691966840, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (801102960).

691966840 is an abundant number, since it is smaller than the sum of its proper divisors (910239080).

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

691966840 is an equidigital number, since it uses as much as digits as its factorization.

691966840 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 385 (or 299 counting only the distinct ones).

The product of its (nonzero) digits is 559872, while the sum is 49.

The square root of 691966840 is about 26305.2625913523. The cubic root of 691966840 is about 884.4944136805.

The spelling of 691966840 in words is "six hundred ninety-one million, nine hundred sixty-six thousand, eight hundred forty".