1213000201981 has 2 divisors, whose sum is σ = 1213000201982. Its totient is φ = 1213000201980.

The previous prime is 1213000201943. The next prime is 1213000202041. The reversal of 1213000201981 is 1891020003121.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 964107972100 + 248892229881 = 981890^2 + 498891^2 .

It is a cyclic number.

It is not a de Polignac number, because 1213000201981 - 2¹¹ = 1213000199933 is a prime.

It is a super-2 number, since 2×1213000201981² (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 (1213000201181) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 606500100990 + 606500100991.

It is an arithmetic number, because the mean of its divisors is an integer number (606500100991).

Almost surely, 2^{1213000201981} is an apocalyptic number.

It is an amenable number.

1213000201981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1213000201981 is an equidigital number, since it uses as much as digits as its factorization.

1213000201981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 864, while the sum is 28.

The spelling of 1213000201981 in words is "one trillion, two hundred thirteen billion, two hundred one thousand, nine hundred eighty-one".