21813019 has 2 divisors, whose sum is σ = 21813020. Its totient is φ = 21813018.

The previous prime is 21813013. The next prime is 21813037. The reversal of 21813019 is 91031812.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21813019 - 2⁷ = 21812891 is a prime.

It is a super-2 number, since 2×21813019² = 951615595788722, which contains 22 as substring.

It is equal to p_1378150 and since 21813019 and 1378150 have the same sum of digits, it is a Honaker prime.

It is a junction number, because it is equal to n+sod(n) for n = 21812984 and 21813002.

It is not a weakly prime, because it can be changed into another prime (21813013) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10906509 + 10906510.

It is an arithmetic number, because the mean of its divisors is an integer number (10906510).

Almost surely, 2^21813019 is an apocalyptic number.

21813019 is a deficient number, since it is larger than the sum of its proper divisors (1).

21813019 is an equidigital number, since it uses as much as digits as its factorization.

21813019 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 432, while the sum is 25.

The square root of 21813019 is about 4670.4409856030. The cubic root of 21813019 is about 279.4078429492.

The spelling of 21813019 in words is "twenty-one million, eight hundred thirteen thousand, nineteen".