19821533141538 has 30 divisors (see below), whose sum is σ = 44415043829409. Its totient is φ = 6607158825024.

The previous prime is 19821533141533. The next prime is 19821533141561. The reversal of 19821533141538 is 83514133512891.

It is a happy number.

19821533141538 is a `hidden beast` number, since 1 + 9 + 8 + 21 + 53 + 31 + 4 + 1 + 538 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 14268879191889 + 5552653949649 = 3777417^2 + 2356407^2 .

It is an ABA number since it can be written as A⋅B^A, here for A=2, B=3148137.

It is a Harshad number since it is a multiple of its sum of digits (54).

It is not an unprimeable number, because it can be changed into a prime (19821533141533) by changing a digit.

It is a polite number, since it can be written in 14 ways as a sum of consecutive naturals, for example, 56491570 + ... + 56841362.

Almost surely, 2^{19821533141538} is an apocalyptic number.

19821533141538 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

19821533141538 is an abundant number, since it is smaller than the sum of its proper divisors (24593510687871).

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

19821533141538 is an frugal number, since it uses more digits than its factorization.

19821533141538 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 699600 (or 349798 counting only the distinct ones).

The product of its digits is 3110400, while the sum is 54.

The spelling of 19821533141538 in words is "nineteen trillion, eight hundred twenty-one billion, five hundred thirty-three million, one hundred forty-one thousand, five hundred thirty-eight".