21389988329 has 2 divisors, whose sum is σ = 21389988330. Its totient is φ = 21389988328.

The previous prime is 21389988307. The next prime is 21389988371. The reversal of 21389988329 is 92388998312.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19241851225 + 2148137104 = 138715^2 + 46348^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21389988329 is a prime.

It is not a weakly prime, because it can be changed into another prime (21389948329) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10694994164 + 10694994165.

It is an arithmetic number, because the mean of its divisors is an integer number (10694994165).

Almost surely, 2^21389988329 is an apocalyptic number.

It is an amenable number.

21389988329 is a deficient number, since it is larger than the sum of its proper divisors (1).

21389988329 is an equidigital number, since it uses as much as digits as its factorization.

21389988329 is an evil number, because the sum of its binary digits is even.

The product of its digits is 13436928, while the sum is 62.

The spelling of 21389988329 in words is "twenty-one billion, three hundred eighty-nine million, nine hundred eighty-eight thousand, three hundred twenty-nine".