21011220019 has 2 divisors, whose sum is σ = 21011220020. Its totient is φ = 21011220018.

The previous prime is 21011219987. The next prime is 21011220049. The reversal of 21011220019 is 91002211012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21011220019 - 2⁵ = 21011219987 is a prime.

It is a super-2 number, since 2×21011220019² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21011219978 and 21011220005.

It is not a weakly prime, because it can be changed into another prime (21011220049) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505610009 + 10505610010.

It is an arithmetic number, because the mean of its divisors is an integer number (10505610010).

Almost surely, 2^21011220019 is an apocalyptic number.

21011220019 is a deficient number, since it is larger than the sum of its proper divisors (1).

21011220019 is an equidigital number, since it uses as much as digits as its factorization.

21011220019 is an evil number, because the sum of its binary digits is even.

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

The spelling of 21011220019 in words is "twenty-one billion, eleven million, two hundred twenty thousand, nineteen".