691989192 has 144 divisors (see below), whose sum is σ = 1977400620. Its totient is φ = 218557440.

The previous prime is 691989169. The next prime is 691989197. The reversal of 691989192 is 291989196.

It can be written as a sum of positive squares in 2 ways, for example, as 687803076 + 4186116 = 26226^2 + 2046^2 .

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (691989197) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 5050948 + ... + 5051084.

Almost surely, 2^691989192 is an apocalyptic number.

691989192 is a gapful number since it is divisible by the number (62) 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 691989192, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (988700310).

691989192 is an abundant number, since it is smaller than the sum of its proper divisors (1285411428).

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

691989192 is a wasteful number, since it uses less digits than its factorization.

691989192 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 284 (or 246 counting only the distinct ones).

The product of its digits is 629856, while the sum is 54.

The square root of 691989192 is about 26305.6874458738. The cubic root of 691989192 is about 884.5039372613.

The spelling of 691989192 in words is "six hundred ninety-one million, nine hundred eighty-nine thousand, one hundred ninety-two".