21103442 has 4 divisors (see below), whose sum is σ = 31655166. Its totient is φ = 10551720.

The previous prime is 21103441. The next prime is 21103451. The reversal of 21103442 is 24430112.

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

It can be written as a sum of positive squares in only one way, i.e., 21058921 + 44521 = 4589^2 + 211^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21103442.

It is not an unprimeable number, because it can be changed into a prime (21103441) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5275859 + ... + 5275862.

Almost surely, 2^21103442 is an apocalyptic number.

21103442 is a deficient number, since it is larger than the sum of its proper divisors (10551724).

21103442 is a wasteful number, since it uses less digits than its factorization.

21103442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10551723.

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

The square root of 21103442 is about 4593.8482778603. The cubic root of 21103442 is about 276.3446737060.

Adding to 21103442 its reverse (24430112), we get a palindrome (45533554).

The spelling of 21103442 in words is "twenty-one million, one hundred three thousand, four hundred forty-two".