821613993508 has 48 divisors (see below), whose sum is σ = 1794704655744. Its totient is φ = 319735722240.

The previous prime is 821613993481. The next prime is 821613993509. The reversal of 821613993508 is 805399316128.

It is a super-2 number, since 2×821613993508² (a number of 25 digits) contains 22 as substring.

It is not an unprimeable number, because it can be changed into a prime (821613993509) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1292391 + ... + 1820302.

It is an arithmetic number, because the mean of its divisors is an integer number (37389680328).

Almost surely, 2^821613993508 is an apocalyptic number.

It is an amenable number.

821613993508 is an abundant number, since it is smaller than the sum of its proper divisors (973090662236).

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

821613993508 is a wasteful number, since it uses less digits than its factorization.

821613993508 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3113572 (or 3113570 counting only the distinct ones).

The product of its (nonzero) digits is 2799360, while the sum is 55.

The spelling of 821613993508 in words is "eight hundred twenty-one billion, six hundred thirteen million, nine hundred ninety-three thousand, five hundred eight".