21121586819 has 2 divisors, whose sum is σ = 21121586820. Its totient is φ = 21121586818.

The previous prime is 21121586809. The next prime is 21121586821. The reversal of 21121586819 is 91868512112.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21121586819 - 2¹² = 21121582723 is a prime.

It is a super-2 number, since 2×21121586819² (a number of 21 digits) contains 22 as substring.

Together with 21121586821, it forms a pair of twin primes.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21121586819.

It is not a weakly prime, because it can be changed into another prime (21121586809) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10560793409 + 10560793410.

It is an arithmetic number, because the mean of its divisors is an integer number (10560793410).

Almost surely, 2^21121586819 is an apocalyptic number.

21121586819 is a deficient number, since it is larger than the sum of its proper divisors (1).

21121586819 is an equidigital number, since it uses as much as digits as its factorization.

21121586819 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69120, while the sum is 44.

The spelling of 21121586819 in words is "twenty-one billion, one hundred twenty-one million, five hundred eighty-six thousand, eight hundred nineteen".