21679143 has 4 divisors (see below), whose sum is σ = 28905528. Its totient is φ = 14452760.

The previous prime is 21679139. The next prime is 21679159. The reversal of 21679143 is 34197612.

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

It is a cyclic number.

It is not a de Polignac number, because 21679143 - 2² = 21679139 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21679183) 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, 3613188 + ... + 3613193.

It is an arithmetic number, because the mean of its divisors is an integer number (7226382).

Almost surely, 2^21679143 is an apocalyptic number.

21679143 is a deficient number, since it is larger than the sum of its proper divisors (7226385).

21679143 is an equidigital number, since it uses as much as digits as its factorization.

21679143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7226384.

The product of its digits is 9072, while the sum is 33.

The square root of 21679143 is about 4656.0866615646. The cubic root of 21679143 is about 278.8350536434.

The spelling of 21679143 in words is "twenty-one million, six hundred seventy-nine thousand, one hundred forty-three".