821437424640 has 1408 divisors, whose sum is σ = 3486280089600. Its totient is φ = 179477544960.

The previous prime is 821437424573. The next prime is 821437424681. The reversal of 821437424640 is 46424734128.

821437424640 is a `hidden beast` number, since 8 + 2 + 143 + 7 + 42 + 464 + 0 = 666.

It is a Harshad number since it is a multiple of its sum of digits (45).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 127 ways as a sum of consecutive naturals, for example, 4169733022 + ... + 4169733218.

It is an arithmetic number, because the mean of its divisors is an integer number (2476051200).

Almost surely, 2^821437424640 is an apocalyptic number.

821437424640 is a gapful number since it is divisible by the number (80) 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 821437424640, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1743140044800).

821437424640 is an abundant number, since it is smaller than the sum of its proper divisors (2664842664960).

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

821437424640 is a wasteful number, since it uses less digits than its factorization.

821437424640 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 408 (or 384 counting only the distinct ones).

The product of its (nonzero) digits is 1032192, while the sum is 45.

The spelling of 821437424640 in words is "eight hundred twenty-one billion, four hundred thirty-seven million, four hundred twenty-four thousand, six hundred forty".