1000211321981 has 2 divisors, whose sum is σ = 1000211321982. Its totient is φ = 1000211321980.

The previous prime is 1000211321959. The next prime is 1000211322031. The reversal of 1000211321981 is 1891231120001.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 970924476025 + 29286845956 = 985355^2 + 171134^2 .

It is an emirp because it is prime and its reverse (1891231120001) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 1000211321981 - 2³⁰ = 999137580157 is a prime.

It is a super-2 number, since 2×1000211321981² (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 (1000211321381) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 500105660990 + 500105660991.

It is an arithmetic number, because the mean of its divisors is an integer number (500105660991).

Almost surely, 2^{1000211321981} is an apocalyptic number.

It is an amenable number.

1000211321981 is a deficient number, since it is larger than the sum of its proper divisors (1).

1000211321981 is an equidigital number, since it uses as much as digits as its factorization.

1000211321981 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 864, while the sum is 29.

Adding to 1000211321981 its reverse (1891231120001), we get a palindrome (2891442441982).

The spelling of 1000211321981 in words is "one trillion, two hundred eleven million, three hundred twenty-one thousand, nine hundred eighty-one".