21000221099989 has 2 divisors, whose sum is σ = 21000221099990. Its totient is φ = 21000221099988.

The previous prime is 21000221099981. The next prime is 21000221100137. The reversal of 21000221099989 is 98999012200012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 17230527035089 + 3769694064900 = 4150967^2 + 1941570^2 .

It is a cyclic number.

It is not a de Polignac number, because 21000221099989 - 2³ = 21000221099981 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21000221099981) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500110549994 + 10500110549995.

It is an arithmetic number, because the mean of its divisors is an integer number (10500110549995).

Almost surely, 2^{21000221099989} is an apocalyptic number.

It is an amenable number.

21000221099989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21000221099989 is an equidigital number, since it uses as much as digits as its factorization.

21000221099989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 419904, while the sum is 52.

The spelling of 21000221099989 in words is "twenty-one trillion, two hundred twenty-one million, ninety-nine thousand, nine hundred eighty-nine".