21821027 has 2 divisors, whose sum is σ = 21821028. Its totient is φ = 21821026.

The previous prime is 21821003. The next prime is 21821039. The reversal of 21821027 is 72012812.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21821027 - 2¹⁸ = 21558883 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21820993 and 21821011.

It is not a weakly prime, because it can be changed into another prime (21821927) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10910513 + 10910514.

It is an arithmetic number, because the mean of its divisors is an integer number (10910514).

Almost surely, 2^21821027 is an apocalyptic number.

21821027 is a deficient number, since it is larger than the sum of its proper divisors (1).

21821027 is an equidigital number, since it uses as much as digits as its factorization.

21821027 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 448, while the sum is 23.

The square root of 21821027 is about 4671.2982135591. The cubic root of 21821027 is about 279.4420308541.

Adding to 21821027 its reverse (72012812), we get a palindrome (93833839).

The spelling of 21821027 in words is "twenty-one million, eight hundred twenty-one thousand, twenty-seven".