21159967 has 8 divisors (see below), whose sum is σ = 21849696. Its totient is φ = 20476512.

The previous prime is 21159953. The next prime is 21159973. The reversal of 21159967 is 76995112.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21159967 - 2¹¹ = 21157919 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 (21159907) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5838 + ... + 8740.

It is an arithmetic number, because the mean of its divisors is an integer number (2731212).

Almost surely, 2^21159967 is an apocalyptic number.

21159967 is a deficient number, since it is larger than the sum of its proper divisors (689729).

21159967 is a wasteful number, since it uses less digits than its factorization.

21159967 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3137.

The product of its digits is 34020, while the sum is 40.

The square root of 21159967 is about 4599.9964130421. The cubic root of 21159967 is about 276.5911809999.

The spelling of 21159967 in words is "twenty-one million, one hundred fifty-nine thousand, nine hundred sixty-seven".