81821753006121 has 24 divisors (see below), whose sum is σ = 122573415959904. Its totient is φ = 54543765769920.

The previous prime is 81821753006113. The next prime is 81821753006131. The reversal of 81821753006121 is 12160035712818.

81821753006121 is a `hidden beast` number, since 8 + 1 + 8 + 21 + 7 + 5 + 3 + 0 + 0 + 612 + 1 = 666.

It is not a de Polignac number, because 81821753006121 - 2³ = 81821753006113 is a prime.

It is a hoax number, since the sum of its digits (45) coincides with the sum of the digits of its distinct prime factors.

It is not an unprimeable number, because it can be changed into a prime (81821753006131) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 9294816 + ... + 15812561.

It is an arithmetic number, because the mean of its divisors is an integer number (5107225664996).

Almost surely, 2^{81821753006121} is an apocalyptic number.

81821753006121 is a gapful number since it is divisible by the number (81) formed by its first and last digit.

It is an amenable number.

81821753006121 is a deficient number, since it is larger than the sum of its proper divisors (40751662953783).

81821753006121 is a wasteful number, since it uses less digits than its factorization.

81821753006121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25120803 (or 25120791 counting only the distinct ones).

The product of its (nonzero) digits is 161280, while the sum is 45.

Adding to 81821753006121 its reverse (12160035712818), we get a palindrome (93981788718939).

The spelling of 81821753006121 in words is "eighty-one trillion, eight hundred twenty-one billion, seven hundred fifty-three million, six thousand, one hundred twenty-one".