21211021019 has 4 divisors (see below), whose sum is σ = 21211419360. Its totient is φ = 21210622680.

The previous prime is 21211021003. The next prime is 21211021081. The reversal of 21211021019 is 91012011212.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 21211021019 - 2⁴ = 21211021003 is a prime.

It is a super-2 number, since 2×21211021019² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21211021219) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 104204 + ... + 230825.

It is an arithmetic number, because the mean of its divisors is an integer number (5302854840).

Almost surely, 2^21211021019 is an apocalyptic number.

21211021019 is a deficient number, since it is larger than the sum of its proper divisors (398341).

21211021019 is an equidigital number, since it uses as much as digits as its factorization.

21211021019 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 398340.

The product of its (nonzero) digits is 72, while the sum is 20.

The spelling of 21211021019 in words is "twenty-one billion, two hundred eleven million, twenty-one thousand, nineteen".