21100442 has 16 divisors (see below), whose sum is σ = 34604064. Its totient is φ = 9570000.

The previous prime is 21100441. The next prime is 21100447. The reversal of 21100442 is 24400112.

It is not an unprimeable number, because it can be changed into a prime (21100441) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13817 + ... + 15267.

It is an arithmetic number, because the mean of its divisors is an integer number (2162754).

Almost surely, 2^21100442 is an apocalyptic number.

21100442 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

21100442 is a deficient number, since it is larger than the sum of its proper divisors (13503622).

21100442 is a wasteful number, since it uses less digits than its factorization.

21100442 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2125.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 21100442 is about 4593.5217426284. The cubic root of 21100442 is about 276.3315783176.

Adding to 21100442 its reverse (24400112), we get a palindrome (45500554).

The spelling of 21100442 in words is "twenty-one million, one hundred thousand, four hundred forty-two".