21100542 has 16 divisors (see below), whose sum is σ = 42534912. Its totient is φ = 6977880.

The previous prime is 21100531. The next prime is 21100543. The reversal of 21100542 is 24500112.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100543) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 13084 + ... + 14607.

It is an arithmetic number, because the mean of its divisors is an integer number (2658432).

Almost surely, 2^21100542 is an apocalyptic number.

21100542 is an abundant number, since it is smaller than the sum of its proper divisors (21434370).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21100542 is a wasteful number, since it uses less digits than its factorization.

21100542 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 27823.

The product of its (nonzero) digits is 80, while the sum is 15.

The square root of 21100542 is about 4593.5326275101. The cubic root of 21100542 is about 276.3320148505.

Adding to 21100542 its reverse (24500112), we get a palindrome (45600654).

The spelling of 21100542 in words is "twenty-one million, one hundred thousand, five hundred forty-two".