21122223001981 has 2 divisors, whose sum is σ = 21122223001982. Its totient is φ = 21122223001980.

The previous prime is 21122223001969. The next prime is 21122223001991. The reversal of 21122223001981 is 18910032222112.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 20739599105625 + 382623896356 = 4554075^2 + 618566^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21122223001981 is a prime.

It is a super-2 number, since 2×21122223001981² (a number of 27 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21122223001991) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10561111500990 + 10561111500991.

It is an arithmetic number, because the mean of its divisors is an integer number (10561111500991).

Almost surely, 2^{21122223001981} is an apocalyptic number.

It is an amenable number.

21122223001981 is a deficient number, since it is larger than the sum of its proper divisors (1).

21122223001981 is an equidigital number, since it uses as much as digits as its factorization.

21122223001981 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6912, while the sum is 34.

The spelling of 21122223001981 in words is "twenty-one trillion, one hundred twenty-two billion, two hundred twenty-three million, one thousand, nine hundred eighty-one".