21429143 has 4 divisors (see below), whose sum is σ = 21650160. Its totient is φ = 21208128.

The previous prime is 21429137. The next prime is 21429167. The reversal of 21429143 is 34192412.

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 21429143 - 2⁴ = 21429127 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 (21429103) 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, 110363 + ... + 110556.

It is an arithmetic number, because the mean of its divisors is an integer number (5412540).

Almost surely, 2^21429143 is an apocalyptic number.

21429143 is a deficient number, since it is larger than the sum of its proper divisors (221017).

21429143 is an equidigital number, since it uses as much as digits as its factorization.

21429143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 221016.

The product of its digits is 1728, while the sum is 26.

The square root of 21429143 is about 4629.1622352214. The cubic root of 21429143 is about 277.7590816869.

The spelling of 21429143 in words is "twenty-one million, four hundred twenty-nine thousand, one hundred forty-three".