21730363 has 2 divisors, whose sum is σ = 21730364. Its totient is φ = 21730362.

The previous prime is 21730321. The next prime is 21730391. The reversal of 21730363 is 36303712.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21730363 is a prime.

It is a super-2 number, since 2×21730363² = 944417352223538, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21730393) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10865181 + 10865182.

It is an arithmetic number, because the mean of its divisors is an integer number (10865182).

Almost surely, 2^21730363 is an apocalyptic number.

21730363 is a deficient number, since it is larger than the sum of its proper divisors (1).

21730363 is an equidigital number, since it uses as much as digits as its factorization.

21730363 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2268, while the sum is 25.

The square root of 21730363 is about 4661.5837437506. The cubic root of 21730363 is about 279.0544765007.

The spelling of 21730363 in words is "twenty-one million, seven hundred thirty thousand, three hundred sixty-three".