821424780 has 192 divisors, whose sum is σ = 2834818560. Its totient is φ = 195782400.

The previous prime is 821424733. The next prime is 821424787. The reversal of 821424780 is 87424128.

It is a hoax number, since the sum of its digits (36) coincides with the sum of the digits of its distinct prime factors.

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

It is not an unprimeable number, because it can be changed into a prime (821424787) by changing a digit.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 361207 + ... + 363473.

It is an arithmetic number, because the mean of its divisors is an integer number (14764680).

Almost surely, 2^821424780 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 821424780, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1417409280).

821424780 is an abundant number, since it is smaller than the sum of its proper divisors (2013393780).

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

821424780 is a wasteful number, since it uses less digits than its factorization.

821424780 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2357 (or 2349 counting only the distinct ones).

The product of its (nonzero) digits is 28672, while the sum is 36.

The square root of 821424780 is about 28660.5090673561. The cubic root of 821424780 is about 936.5319543575.

The spelling of 821424780 in words is "eight hundred twenty-one million, four hundred twenty-four thousand, seven hundred eighty".