823191640 has 32 divisors (see below), whose sum is σ = 1854070560. Its totient is φ = 328940800.

The previous prime is 823191619. The next prime is 823191673. The reversal of 823191640 is 46191328.

It is a junction number, because it is equal to n+sod(n) for n = 823191596 and 823191605.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 31260 + ... + 51220.

It is an arithmetic number, because the mean of its divisors is an integer number (57939705).

Almost surely, 2^823191640 is an apocalyptic number.

It is an amenable number.

823191640 is an abundant number, since it is smaller than the sum of its proper divisors (1030878920).

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

823191640 is a wasteful number, since it uses less digits than its factorization.

823191640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 21003 (or 20999 counting only the distinct ones).

The product of its (nonzero) digits is 10368, while the sum is 34.

The square root of 823191640 is about 28691.3164563775. The cubic root of 823191640 is about 937.2029575082.

The spelling of 823191640 in words is "eight hundred twenty-three million, one hundred ninety-one thousand, six hundred forty".