821405396 has 24 divisors (see below), whose sum is σ = 1699461120. Its totient is φ = 339891552.

The previous prime is 821405383. The next prime is 821405399. The reversal of 821405396 is 693504128.

It is a happy number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821405399) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 504980 + ... + 506603.

It is an arithmetic number, because the mean of its divisors is an integer number (70810880).

Almost surely, 2^821405396 is an apocalyptic number.

It is an amenable number.

821405396 is an abundant number, since it is smaller than the sum of its proper divisors (878055724).

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

821405396 is a wasteful number, since it uses less digits than its factorization.

821405396 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1011623 (or 1011621 counting only the distinct ones).

The product of its (nonzero) digits is 51840, while the sum is 38.

The square root of 821405396 is about 28660.1708996998. The cubic root of 821405396 is about 936.5245875324.

The spelling of 821405396 in words is "eight hundred twenty-one million, four hundred five thousand, three hundred ninety-six".