21002199989 has 2 divisors, whose sum is σ = 21002199990. Its totient is φ = 21002199988.

The previous prime is 21002199983. The next prime is 21002200097. The reversal of 21002199989 is 98999120012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20781528964 + 220671025 = 144158^2 + 14855^2 .

It is a cyclic number.

It is not a de Polignac number, because 21002199989 - 2⁴ = 21002199973 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21002199983) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501099994 + 10501099995.

It is an arithmetic number, because the mean of its divisors is an integer number (10501099995).

Almost surely, 2^21002199989 is an apocalyptic number.

It is an amenable number.

21002199989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002199989 is an equidigital number, since it uses as much as digits as its factorization.

21002199989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 209952, while the sum is 50.

The spelling of 21002199989 in words is "twenty-one billion, two million, one hundred ninety-nine thousand, nine hundred eighty-nine".