21304963 has 2 divisors, whose sum is σ = 21304964. Its totient is φ = 21304962.

The previous prime is 21304951. The next prime is 21304973. The reversal of 21304963 is 36940312.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21304963 - 2⁵ = 21304931 is a prime.

It is not a weakly prime, because it can be changed into another prime (21304973) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10652481 + 10652482.

It is an arithmetic number, because the mean of its divisors is an integer number (10652482).

Almost surely, 2^21304963 is an apocalyptic number.

21304963 is a deficient number, since it is larger than the sum of its proper divisors (1).

21304963 is an equidigital number, since it uses as much as digits as its factorization.

21304963 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 3888, while the sum is 28.

The square root of 21304963 is about 4615.7299531060. The cubic root of 21304963 is about 277.2215121355.

The spelling of 21304963 in words is "twenty-one million, three hundred four thousand, nine hundred sixty-three".