821611413504 has 840 divisors, whose sum is σ = 2915573058048. Its totient is φ = 226457026560.

The previous prime is 821611413503. The next prime is 821611413509. The reversal of 821611413504 is 405314116128.

821611413504 is a `hidden beast` number, since 8 + 2 + 1 + 6 + 1 + 141 + 3 + 504 = 666.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (821611413503) by changing a digit.

It is a polite number, since it can be written in 55 ways as a sum of consecutive naturals, for example, 2591833954 + ... + 2591834270.

Almost surely, 2^821611413504 is an apocalyptic number.

821611413504 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 821611413504, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1457786529024).

821611413504 is an abundant number, since it is smaller than the sum of its proper divisors (2093961644544).

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

821611413504 is an frugal number, since it uses more digits than its factorization.

821611413504 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 401 (or 360 counting only the distinct ones).

The product of its (nonzero) digits is 23040, while the sum is 36.

The spelling of 821611413504 in words is "eight hundred twenty-one billion, six hundred eleven million, four hundred thirteen thousand, five hundred four".