21320203 has 2 divisors, whose sum is σ = 21320204. Its totient is φ = 21320202.

The previous prime is 21320197. The next prime is 21320209. The reversal of 21320203 is 30202312.

It is a happy number.

It is a balanced prime because it is at equal distance from previous prime (21320197) and next prime (21320209).

It is a cyclic number.

It is not a de Polignac number, because 21320203 - 2¹⁷ = 21189131 is a prime.

It is a super-2 number, since 2×21320203² = 909102111922418, which contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21320209) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10660101 + 10660102.

It is an arithmetic number, because the mean of its divisors is an integer number (10660102).

Almost surely, 2^21320203 is an apocalyptic number.

21320203 is a deficient number, since it is larger than the sum of its proper divisors (1).

21320203 is an equidigital number, since it uses as much as digits as its factorization.

21320203 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 72, while the sum is 13.

The square root of 21320203 is about 4617.3805344589. The cubic root of 21320203 is about 277.2875976584.

Adding to 21320203 its reverse (30202312), we get a palindrome (51522515).

The spelling of 21320203 in words is "twenty-one million, three hundred twenty thousand, two hundred three".