21020101919 has 2 divisors, whose sum is σ = 21020101920. Its totient is φ = 21020101918.

The previous prime is 21020101909. The next prime is 21020102009. The reversal of 21020101919 is 91910102012.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21020101919 - 2⁴ = 21020101903 is a prime.

It is a super-2 number, since 2×21020101919² (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 (21020101909) 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, 10510050959 + 10510050960.

It is an arithmetic number, because the mean of its divisors is an integer number (10510050960).

Almost surely, 2^21020101919 is an apocalyptic number.

21020101919 is a deficient number, since it is larger than the sum of its proper divisors (1).

21020101919 is an equidigital number, since it uses as much as digits as its factorization.

21020101919 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 324, while the sum is 26.

The spelling of 21020101919 in words is "twenty-one billion, twenty million, one hundred one thousand, nine hundred nineteen".