21002121659 has 2 divisors, whose sum is σ = 21002121660. Its totient is φ = 21002121658.

The previous prime is 21002121649. The next prime is 21002121661. The reversal of 21002121659 is 95612120012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21002121659 - 2⁴ = 21002121643 is a prime.

It is a super-2 number, since 2×21002121659² (a number of 21 digits) contains 22 as substring.

It is a Sophie Germain prime.

Together with 21002121661, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21002121649) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10501060829 + 10501060830.

It is an arithmetic number, because the mean of its divisors is an integer number (10501060830).

Almost surely, 2^21002121659 is an apocalyptic number.

21002121659 is a deficient number, since it is larger than the sum of its proper divisors (1).

21002121659 is an equidigital number, since it uses as much as digits as its factorization.

21002121659 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2160, while the sum is 29.

The spelling of 21002121659 in words is "twenty-one billion, two million, one hundred twenty-one thousand, six hundred fifty-nine".