21163679 has 4 divisors (see below), whose sum is σ = 21174384. Its totient is φ = 21152976.

The previous prime is 21163643. The next prime is 21163687. The reversal of 21163679 is 97636112.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21163679 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 (21163699) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1427 + ... + 6660.

It is an arithmetic number, because the mean of its divisors is an integer number (5293596).

Almost surely, 2^21163679 is an apocalyptic number.

21163679 is a deficient number, since it is larger than the sum of its proper divisors (10705).

21163679 is an equidigital number, since it uses as much as digits as its factorization.

21163679 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10704.

The product of its digits is 13608, while the sum is 35.

The square root of 21163679 is about 4600.3998739240. The cubic root of 21163679 is about 276.6073537793.

The spelling of 21163679 in words is "twenty-one million, one hundred sixty-three thousand, six hundred seventy-nine".