21946159 has 4 divisors (see below), whose sum is σ = 23101240. Its totient is φ = 20791080.

The previous prime is 21946139. The next prime is 21946181. The reversal of 21946159 is 95164912.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21946159 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21946139) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 577512 + ... + 577549.

It is an arithmetic number, because the mean of its divisors is an integer number (5775310).

Almost surely, 2^21946159 is an apocalyptic number.

21946159 is a deficient number, since it is larger than the sum of its proper divisors (1155081).

21946159 is a wasteful number, since it uses less digits than its factorization.

21946159 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1155080.

The product of its digits is 19440, while the sum is 37.

The square root of 21946159 is about 4684.6727740580. The cubic root of 21946159 is about 279.9751636134.

The spelling of 21946159 in words is "twenty-one million, nine hundred forty-six thousand, one hundred fifty-nine".