1000013201981 has 2 divisors, whose sum is σ = 1000013201982. Its totient is φ = 1000013201980.

The previous prime is 1000013201923. The next prime is 1000013202047. The reversal of 1000013201981 is 1891023100001.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 525829469881 + 474183732100 = 725141^2 + 688610^2 .

It is a cyclic number.

It is not a de Polignac number, because 1000013201981 - 2³⁸ = 725135295037 is a prime.

It is a super-2 number, since 2×1000013201981² (a number of 25 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 1000013201981.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (1000013207981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500006600990 + 500006600991.

It is an arithmetic number, because the mean of its divisors is an integer number (500006600991).

Almost surely, 2^{1000013201981} is an apocalyptic number.

It is an amenable number.

1000013201981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1000013201981 is an equidigital number, since it uses as much as digits as its factorization.

1000013201981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 26.

Adding to 1000013201981 its reverse (1891023100001), we get a palindrome (2891036301982).

The spelling of 1000013201981 in words is "one trillion, thirteen million, two hundred one thousand, nine hundred eighty-one".