21312098989 has 2 divisors, whose sum is σ = 21312098990. Its totient is φ = 21312098988.

The previous prime is 21312098971. The next prime is 21312099001. The reversal of 21312098989 is 98989021312.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 18211502500 + 3100596489 = 134950^2 + 55683^2 .

It is a cyclic number.

It is not a de Polignac number, because 21312098989 - 2⁷ = 21312098861 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21312098939) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10656049494 + 10656049495.

It is an arithmetic number, because the mean of its divisors is an integer number (10656049495).

Almost surely, 2^21312098989 is an apocalyptic number.

It is an amenable number.

21312098989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21312098989 is an equidigital number, since it uses as much as digits as its factorization.

21312098989 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 559872, while the sum is 52.

The spelling of 21312098989 in words is "twenty-one billion, three hundred twelve million, ninety-eight thousand, nine hundred eighty-nine".