21102443 has 4 divisors (see below), whose sum is σ = 21209760. Its totient is φ = 20995128.

The previous prime is 21102439. The next prime is 21102451. The reversal of 21102443 is 34420112.

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 21102443 - 2² = 21102439 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21102463) 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, 53363 + ... + 53756.

It is an arithmetic number, because the mean of its divisors is an integer number (5302440).

Almost surely, 2^21102443 is an apocalyptic number.

21102443 is a deficient number, since it is larger than the sum of its proper divisors (107317).

21102443 is a wasteful number, since it uses less digits than its factorization.

21102443 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 107316.

The product of its (nonzero) digits is 192, while the sum is 17.

The square root of 21102443 is about 4593.7395442058. The cubic root of 21102443 is about 276.3403130795.

Adding to 21102443 its reverse (34420112), we get a palindrome (55522555).

The spelling of 21102443 in words is "twenty-one million, one hundred two thousand, four hundred forty-three".