21102042 has 16 divisors (see below), whose sum is σ = 45450720. Its totient is φ = 6492912.

The previous prime is 21102023. The next prime is 21102047. The reversal of 21102042 is 24020112.

It is not an unprimeable number, because it can be changed into a prime (21102047) 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, 135192 + ... + 135347.

It is an arithmetic number, because the mean of its divisors is an integer number (2840670).

Almost surely, 2^21102042 is an apocalyptic number.

21102042 is an abundant number, since it is smaller than the sum of its proper divisors (24348678).

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

21102042 is a wasteful number, since it uses less digits than its factorization.

21102042 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 270557.

The product of its (nonzero) digits is 32, while the sum is 12.

The square root of 21102042 is about 4593.6958976406. The cubic root of 21102042 is about 276.3385626792.

Adding to 21102042 its reverse (24020112), we get a palindrome (45122154).

The spelling of 21102042 in words is "twenty-one million, one hundred two thousand, forty-two".