821929810464 has 384 divisors, whose sum is σ = 2791331020800. Its totient is φ = 230453683200.

The previous prime is 821929810463. The next prime is 821929810489. The reversal of 821929810464 is 464018929128.

It is a happy number.

821929810464 is a `hidden beast` number, since 8 + 2 + 1 + 92 + 98 + 1 + 0 + 464 = 666.

It is a super-2 number, since 2×821929810464² (a number of 25 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is a self number, because there is not a number n which added to its sum of digits gives 821929810464.

It is not an unprimeable number, because it can be changed into a prime (821929810463) 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, 79786114 + ... + 79796414.

It is an arithmetic number, because the mean of its divisors is an integer number (7269091200).

Almost surely, 2^821929810464 is an apocalyptic number.

821929810464 is a gapful number since it is divisible by the number (84) 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 821929810464, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1395665510400).

821929810464 is an abundant number, since it is smaller than the sum of its proper divisors (1969401210336).

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

821929810464 is a wasteful number, since it uses less digits than its factorization.

821929810464 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10573 (or 10559 counting only the distinct ones).

The product of its (nonzero) digits is 1990656, while the sum is 54.

The spelling of 821929810464 in words is "eight hundred twenty-one billion, nine hundred twenty-nine million, eight hundred ten thousand, four hundred sixty-four".