21104542 has 4 divisors (see below), whose sum is σ = 31656816. Its totient is φ = 10552270.

The previous prime is 21104527. The next prime is 21104543. The reversal of 21104542 is 24540112.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21104543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 5276134 + ... + 5276137.

It is an arithmetic number, because the mean of its divisors is an integer number (7914204).

Almost surely, 2^21104542 is an apocalyptic number.

21104542 is a deficient number, since it is larger than the sum of its proper divisors (10552274).

21104542 is a wasteful number, since it uses less digits than its factorization.

21104542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10552273.

The product of its (nonzero) digits is 320, while the sum is 19.

The square root of 21104542 is about 4593.9680016300. The cubic root of 21104542 is about 276.3494750374.

Adding to 21104542 its reverse (24540112), we get a palindrome (45644654).

The spelling of 21104542 in words is "twenty-one million, one hundred four thousand, five hundred forty-two".