1020000121981 has 2 divisors, whose sum is σ = 1020000121982. Its totient is φ = 1020000121980.

The previous prime is 1020000121969. The next prime is 1020000122083. The reversal of 1020000121981 is 1891210000201.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 995385336100 + 24614785881 = 997690^2 + 156891^2 .

It is a cyclic number.

It is not a de Polignac number, because 1020000121981 - 2⁵ = 1020000121949 is a prime.

It is a super-2 number, since 2×1020000121981² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1020000161981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 510000060990 + 510000060991.

It is an arithmetic number, because the mean of its divisors is an integer number (510000060991).

Almost surely, 2^{1020000121981} is an apocalyptic number.

It is an amenable number.

1020000121981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1020000121981 is an equidigital number, since it uses as much as digits as its factorization.

1020000121981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 288, while the sum is 25.

The spelling of 1020000121981 in words is "one trillion, twenty billion, one hundred twenty-one thousand, nine hundred eighty-one".