691855140 has 96 divisors (see below), whose sum is σ = 1973422080. Its totient is φ = 181074816.

The previous prime is 691855123. The next prime is 691855159. The reversal of 691855140 is 41558196.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1075659 + ... + 1076301.

It is an arithmetic number, because the mean of its divisors is an integer number (20556480).

Almost surely, 2^691855140 is an apocalyptic number.

691855140 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 691855140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (986711040).

691855140 is an abundant number, since it is smaller than the sum of its proper divisors (1281566940).

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

691855140 is a wasteful number, since it uses less digits than its factorization.

691855140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 961 (or 959 counting only the distinct ones).

The product of its (nonzero) digits is 43200, while the sum is 39.

The square root of 691855140 is about 26303.1393563582. The cubic root of 691855140 is about 884.4468182675.

The spelling of 691855140 in words is "six hundred ninety-one million, eight hundred fifty-five thousand, one hundred forty".