21425143 has 4 divisors (see below), whose sum is σ = 21442960. Its totient is φ = 21407328.

The previous prime is 21425099. The next prime is 21425147. The reversal of 21425143 is 34152412.

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 21425143 - 2⁹ = 21424631 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 (21425147) 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, 6963 + ... + 9556.

It is an arithmetic number, because the mean of its divisors is an integer number (5360740).

Almost surely, 2^21425143 is an apocalyptic number.

21425143 is a deficient number, since it is larger than the sum of its proper divisors (17817).

21425143 is a wasteful number, since it uses less digits than its factorization.

21425143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 17816.

The product of its digits is 960, while the sum is 22.

The square root of 21425143 is about 4628.7301714401. The cubic root of 21425143 is about 277.7417982851.

Adding to 21425143 its reverse (34152412), we get a palindrome (55577555).

The spelling of 21425143 in words is "twenty-one million, four hundred twenty-five thousand, one hundred forty-three".