19821620197836 has 144 divisors (see below), whose sum is σ = 52168062256128. Its totient is φ = 6338978006400.

The previous prime is 19821620197831. The next prime is 19821620197853. The reversal of 19821620197836 is 63879102612891.

It is not an unprimeable number, because it can be changed into a prime (19821620197831) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 77491231 + ... + 77746601.

It is an arithmetic number, because the mean of its divisors is an integer number (362278210112).

Almost surely, 2^{19821620197836} 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 19821620197836, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (26084031128064).

19821620197836 is an abundant number, since it is smaller than the sum of its proper divisors (32346442058292).

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

19821620197836 is a wasteful number, since it uses less digits than its factorization.

19821620197836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 256012 (or 256007 counting only the distinct ones).

The product of its (nonzero) digits is 15676416, while the sum is 63.

The spelling of 19821620197836 in words is "nineteen trillion, eight hundred twenty-one billion, six hundred twenty million, one hundred ninety-seven thousand, eight hundred thirty-six".