21955943 has 2 divisors, whose sum is σ = 21955944. Its totient is φ = 21955942.

The previous prime is 21955933. The next prime is 21955957. The reversal of 21955943 is 34955912.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21955943 - 2¹² = 21951847 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21955897 and 21955906.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21955933) 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, 10977971 + 10977972.

It is an arithmetic number, because the mean of its divisors is an integer number (10977972).

Almost surely, 2^21955943 is an apocalyptic number.

21955943 is a deficient number, since it is larger than the sum of its proper divisors (1).

21955943 is an equidigital number, since it uses as much as digits as its factorization.

21955943 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 48600, while the sum is 38.

The square root of 21955943 is about 4685.7169141979. The cubic root of 21955943 is about 280.0167634521.

The spelling of 21955943 in words is "twenty-one million, nine hundred fifty-five thousand, nine hundred forty-three".