21101021489 has 2 divisors, whose sum is σ = 21101021490. Its totient is φ = 21101021488.

The previous prime is 21101021479. The next prime is 21101021507. The reversal of 21101021489 is 98412010112.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16561630864 + 4539390625 = 128692^2 + 67375^2 .

It is a cyclic number.

It is not a de Polignac number, because 21101021489 - 2¹² = 21101017393 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (21101021479) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10550510744 + 10550510745.

It is an arithmetic number, because the mean of its divisors is an integer number (10550510745).

Almost surely, 2^21101021489 is an apocalyptic number.

It is an amenable number.

21101021489 is a deficient number, since it is larger than the sum of its proper divisors (1).

21101021489 is an equidigital number, since it uses as much as digits as its factorization.

21101021489 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1152, while the sum is 29.

The spelling of 21101021489 in words is "twenty-one billion, one hundred one million, twenty-one thousand, four hundred eighty-nine".