21361143 has 4 divisors (see below), whose sum is σ = 28481528. Its totient is φ = 14240760.

The previous prime is 21361133. The next prime is 21361147. The reversal of 21361143 is 34116312.

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

It is not a de Polignac number, because 21361143 - 2⁶ = 21361079 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 (21361147) 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, 3560188 + ... + 3560193.

It is an arithmetic number, because the mean of its divisors is an integer number (7120382).

Almost surely, 2^21361143 is an apocalyptic number.

21361143 is a deficient number, since it is larger than the sum of its proper divisors (7120385).

21361143 is an equidigital number, since it uses as much as digits as its factorization.

21361143 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7120384.

The product of its digits is 432, while the sum is 21.

The square root of 21361143 is about 4621.8116577810. The cubic root of 21361143 is about 277.4649708239.

Adding to 21361143 its reverse (34116312), we get a palindrome (55477455).

The spelling of 21361143 in words is "twenty-one million, three hundred sixty-one thousand, one hundred forty-three".