21102021019 has 2 divisors, whose sum is σ = 21102021020. Its totient is φ = 21102021018.

The previous prime is 21102020987. The next prime is 21102021023. The reversal of 21102021019 is 91012020112.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21102021019 - 2⁵ = 21102020987 is a prime.

It is a super-2 number, since 2×21102021019² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21102020987 and 21102021005.

It is not a weakly prime, because it can be changed into another prime (21102021049) 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, 10551010509 + 10551010510.

It is an arithmetic number, because the mean of its divisors is an integer number (10551010510).

Almost surely, 2^21102021019 is an apocalyptic number.

21102021019 is a deficient number, since it is larger than the sum of its proper divisors (1).

21102021019 is an equidigital number, since it uses as much as digits as its factorization.

21102021019 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 72, while the sum is 19.

The spelling of 21102021019 in words is "twenty-one billion, one hundred two million, twenty-one thousand, nineteen".