691131168 has 144 divisors (see below), whose sum is σ = 2419050816. Its totient is φ = 182269440.

The previous prime is 691131167. The next prime is 691131169. The reversal of 691131168 is 861131196.

It is a happy number.

It is an interprime number because it is at equal distance from previous prime (691131167) and next prime (691131169).

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a nude number because it is divisible by every one of its digits.

It is not an unprimeable number, because it can be changed into a prime (691131167) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 13023 + ... + 39393.

It is an arithmetic number, because the mean of its divisors is an integer number (16798964).

Almost surely, 2^691131168 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 691131168, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1209525408).

691131168 is an abundant number, since it is smaller than the sum of its proper divisors (1727919648).

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

691131168 is a wasteful number, since it uses less digits than its factorization.

691131168 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26407 (or 26396 counting only the distinct ones).

The product of its digits is 7776, while the sum is 36.

The square root of 691131168 is about 26289.3736707439. The cubic root of 691131168 is about 884.1382092485.

The spelling of 691131168 in words is "six hundred ninety-one million, one hundred thirty-one thousand, one hundred sixty-eight".