21012230989 has 2 divisors, whose sum is σ = 21012230990. Its totient is φ = 21012230988.

The previous prime is 21012230977. The next prime is 21012231041. The reversal of 21012230989 is 98903221012.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 20331908100 + 680322889 = 142590^2 + 26083^2 .

It is a cyclic number.

It is not a de Polignac number, because 21012230989 - 2²⁹ = 20475360077 is a prime.

It is a super-2 number, since 2×21012230989² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21012230909) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506115494 + 10506115495.

It is an arithmetic number, because the mean of its divisors is an integer number (10506115495).

Almost surely, 2^21012230989 is an apocalyptic number.

It is an amenable number.

21012230989 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012230989 is an equidigital number, since it uses as much as digits as its factorization.

21012230989 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 15552, while the sum is 37.

The spelling of 21012230989 in words is "twenty-one billion, twelve million, two hundred thirty thousand, nine hundred eighty-nine".