21012321289 has 2 divisors, whose sum is σ = 21012321290. Its totient is φ = 21012321288.

The previous prime is 21012321259. The next prime is 21012321371. The reversal of 21012321289 is 98212321012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16252425225 + 4759896064 = 127485^2 + 68992^2 .

It is a cyclic number.

It is not a de Polignac number, because 21012321289 - 2¹⁷ = 21012190217 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21012321289.

It is not a weakly prime, because it can be changed into another prime (21012321259) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506160644 + 10506160645.

It is an arithmetic number, because the mean of its divisors is an integer number (10506160645).

Almost surely, 2^21012321289 is an apocalyptic number.

It is an amenable number.

21012321289 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012321289 is an equidigital number, since it uses as much as digits as its factorization.

21012321289 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3456, while the sum is 31.

The spelling of 21012321289 in words is "twenty-one billion, twelve million, three hundred twenty-one thousand, two hundred eighty-nine".