21889690609 has 2 divisors, whose sum is σ = 21889690610. Its totient is φ = 21889690608.

The previous prime is 21889690591. The next prime is 21889690661. The reversal of 21889690609 is 90609698812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 14424730609 + 7464960000 = 120103^2 + 86400^2 .

It is a cyclic number.

It is not a de Polignac number, because 21889690609 - 2¹³ = 21889682417 is a prime.

It is not a weakly prime, because it can be changed into another prime (21889690699) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10944845304 + 10944845305.

It is an arithmetic number, because the mean of its divisors is an integer number (10944845305).

Almost surely, 2^21889690609 is an apocalyptic number.

It is an amenable number.

21889690609 is a deficient number, since it is larger than the sum of its proper divisors (1).

21889690609 is an equidigital number, since it uses as much as digits as its factorization.

21889690609 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3359232, while the sum is 58.

The spelling of 21889690609 in words is "twenty-one billion, eight hundred eighty-nine million, six hundred ninety thousand, six hundred nine".