21202019 has 4 divisors (see below), whose sum is σ = 21211440. Its totient is φ = 21192600.

The previous prime is 21202003. The next prime is 21202033. The reversal of 21202019 is 91020212.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 21202019 - 2⁴ = 21202003 is a prime.

It is a super-2 number, since 2×21202019² = 899051219352722, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21201988 and 21202006.

It is not an unprimeable number, because it can be changed into a prime (21202039) 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, 869 + ... + 6569.

It is an arithmetic number, because the mean of its divisors is an integer number (5302860).

Almost surely, 2^21202019 is an apocalyptic number.

21202019 is a deficient number, since it is larger than the sum of its proper divisors (9421).

21202019 is an equidigital number, since it uses as much as digits as its factorization.

21202019 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9420.

The product of its (nonzero) digits is 72, while the sum is 17.

The square root of 21202019 is about 4604.5650174582. The cubic root of 21202019 is about 276.7742864491.

It can be divided in two parts, 2 and 1202019, that added together give a palindrome (1202021).

The spelling of 21202019 in words is "twenty-one million, two hundred two thousand, nineteen".