21963947 has 2 divisors, whose sum is σ = 21963948. Its totient is φ = 21963946.

The previous prime is 21963917. The next prime is 21963959. The reversal of 21963947 is 74936912.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21963947 - 2⁶ = 21963883 is a prime.

It is not a weakly prime, because it can be changed into another prime (21963917) 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, 10981973 + 10981974.

It is an arithmetic number, because the mean of its divisors is an integer number (10981974).

Almost surely, 2^21963947 is an apocalyptic number.

21963947 is a deficient number, since it is larger than the sum of its proper divisors (1).

21963947 is an equidigital number, since it uses as much as digits as its factorization.

21963947 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 81648, while the sum is 41.

The square root of 21963947 is about 4686.5709212600. The cubic root of 21963947 is about 280.0507858560.

The spelling of 21963947 in words is "twenty-one million, nine hundred sixty-three thousand, nine hundred forty-seven".