21532143 has 4 divisors (see below), whose sum is σ = 28709528. Its totient is φ = 14354760.

The previous prime is 21532097. The next prime is 21532169. The reversal of 21532143 is 34123512.

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

It is not a de Polignac number, because 21532143 - 2¹⁰ = 21531119 is a prime.

It is a Duffinian number.

It is a plaindrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21532843) 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, 3588688 + ... + 3588693.

It is an arithmetic number, because the mean of its divisors is an integer number (7177382).

Almost surely, 2^21532143 is an apocalyptic number.

21532143 is a deficient number, since it is larger than the sum of its proper divisors (7177385).

21532143 is an equidigital number, since it uses as much as digits as its factorization.

21532143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7177384.

The product of its digits is 720, while the sum is 21.

The square root of 21532143 is about 4640.2740220810. The cubic root of 21532143 is about 278.2033904859.

Adding to 21532143 its reverse (34123512), we get a palindrome (55655655).

The spelling of 21532143 in words is "twenty-one million, five hundred thirty-two thousand, one hundred forty-three".