21620143 has 4 divisors (see below), whose sum is σ = 21632728. Its totient is φ = 21607560.

The previous prime is 21620129. The next prime is 21620153. The reversal of 21620143 is 34102612.

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 21620143 - 2⁵ = 21620111 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21620143.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21620153) 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, 3213 + ... + 7318.

It is an arithmetic number, because the mean of its divisors is an integer number (5408182).

Almost surely, 2^21620143 is an apocalyptic number.

21620143 is a deficient number, since it is larger than the sum of its proper divisors (12585).

21620143 is a wasteful number, since it uses less digits than its factorization.

21620143 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12584.

The product of its (nonzero) digits is 288, while the sum is 19.

The square root of 21620143 is about 4649.7465522327. The cubic root of 21620143 is about 278.5818730501.

Adding to 21620143 its reverse (34102612), we get a palindrome (55722755).

The spelling of 21620143 in words is "twenty-one million, six hundred twenty thousand, one hundred forty-three".