823421664 has 72 divisors (see below), whose sum is σ = 2521740312. Its totient is φ = 253359360.

The previous prime is 823421653. The next prime is 823421701. The reversal of 823421664 is 466124328.

It is a tau number, because it is divible by the number of its divisors (72).

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 a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 106222 + ... + 113709.

It is an arithmetic number, because the mean of its divisors is an integer number (35024171).

Almost surely, 2^823421664 is an apocalyptic number.

It is an amenable number.

823421664 is an abundant number, since it is smaller than the sum of its proper divisors (1698318648).

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

823421664 is a wasteful number, since it uses less digits than its factorization.

823421664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 219960 (or 219949 counting only the distinct ones).

The product of its digits is 55296, while the sum is 36.

The square root of 823421664 is about 28695.3247759979. The cubic root of 823421664 is about 937.2902434192.

The spelling of 823421664 in words is "eight hundred twenty-three million, four hundred twenty-one thousand, six hundred sixty-four".