821297630520 has 384 divisors, whose sum is σ = 2916856051200. Its totient is φ = 207265734144.

The previous prime is 821297630507. The next prime is 821297630551. The reversal of 821297630520 is 25036792128.

821297630520 is a `hidden beast` number, since 8 + 2 + 1 + 2 + 9 + 7 + 630 + 5 + 2 + 0 = 666.

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

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 95 ways as a sum of consecutive naturals, for example, 240636334 + ... + 240639746.

It is an arithmetic number, because the mean of its divisors is an integer number (7595979300).

Almost surely, 2^821297630520 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 821297630520, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1458428025600).

821297630520 is an abundant number, since it is smaller than the sum of its proper divisors (2095558420680).

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

821297630520 is a wasteful number, since it uses less digits than its factorization.

821297630520 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4761 (or 4745 counting only the distinct ones).

The product of its (nonzero) digits is 362880, while the sum is 45.

The spelling of 821297630520 in words is "eight hundred twenty-one billion, two hundred ninety-seven million, six hundred thirty thousand, five hundred twenty".