21001021219 has 2 divisors, whose sum is σ = 21001021220. Its totient is φ = 21001021218.

The previous prime is 21001021187. The next prime is 21001021229. The reversal of 21001021219 is 91212010012.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21001021219 - 2⁵ = 21001021187 is a prime.

It is a super-2 number, since 2×21001021219² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21001021196 and 21001021205.

It is not a weakly prime, because it can be changed into another prime (21001021229) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10500510609 + 10500510610.

It is an arithmetic number, because the mean of its divisors is an integer number (10500510610).

Almost surely, 2^21001021219 is an apocalyptic number.

21001021219 is a deficient number, since it is larger than the sum of its proper divisors (1).

21001021219 is an equidigital number, since it uses as much as digits as its factorization.

21001021219 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 21001021219 in words is "twenty-one billion, one million, twenty-one thousand, two hundred nineteen".