21021383 has 2 divisors, whose sum is σ = 21021384. Its totient is φ = 21021382.

The previous prime is 21021359. The next prime is 21021389. The reversal of 21021383 is 38312012.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21021383 - 2⁸ = 21021127 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21021389) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10510691 + 10510692.

It is an arithmetic number, because the mean of its divisors is an integer number (10510692).

Almost surely, 2^21021383 is an apocalyptic number.

21021383 is a deficient number, since it is larger than the sum of its proper divisors (1).

21021383 is an equidigital number, since it uses as much as digits as its factorization.

21021383 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 288, while the sum is 20.

The square root of 21021383 is about 4584.9081779246. The cubic root of 21021383 is about 275.9860272629.

Adding to 21021383 its reverse (38312012), we get a palindrome (59333395).

The spelling of 21021383 in words is "twenty-one million, twenty-one thousand, three hundred eighty-three".