221221011989 has 2 divisors, whose sum is σ = 221221011990. Its totient is φ = 221221011988.

The previous prime is 221221011959. The next prime is 221221012007. The reversal of 221221011989 is 989110122122.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 219930047089 + 1290964900 = 468967^2 + 35930^2 .

It is a cyclic number.

It is not a de Polignac number, because 221221011989 - 2²⁰ = 221219963413 is a prime.

It is a super-2 number, since 2×221221011989² (a number of 23 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (221221011959) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 110610505994 + 110610505995.

It is an arithmetic number, because the mean of its divisors is an integer number (110610505995).

Almost surely, 2^221221011989 is an apocalyptic number.

It is an amenable number.

221221011989 is a deficient number, since it is larger than the sum of its proper divisors (1).

221221011989 is an equidigital number, since it uses as much as digits as its factorization.

221221011989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 10368, while the sum is 38.

The spelling of 221221011989 in words is "two hundred twenty-one billion, two hundred twenty-one million, eleven thousand, nine hundred eighty-nine".